How Senna won his greatest F1 title

The 1991 Formula 1 contest is not as famous as the controversial seasons that preceded it, but you could make a strong case for it being Ayrton Senna's finest championship success.

The year is often recalled as one that was decided by Senna's quartet of victories for McLaren at the beginning of the campaign, scored while Williams struggled with unreliability.

That start certainly laid good foundations for the Brazilian - after four rounds Senna was 29 points ahead, with eventual main challenger Nigel Mansell 34 behind - but the battle was harder than that suggests, requiring a strong response after Mansell's three straight wins got him within genuine striking distance.

The threat from Williams-Renault to McLaren-Honda's domination emerged quickly. As early as round two in Brazil Mansell chased Senna hard - and set fastest lap - before going out due to problems with his FW14's semi-automatic gearbox. Even then, Senna was forced to pull out one of his greatest drives, nursing his MP4/6 home in sixth gear as Riccardo Patrese's Williams closed in.

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Patrese, who put in one of his best seasons despite a number of poor getaways, led brilliantly in the wet next time out at Imola until a misfire intervened. That left McLaren to score a 1-2, Senna leading Gerhard Berger, with no other frontrunners finishing.

Senna dominated at Monaco, but Mansell scored his first 1991 points with second and then Williams qualified 1-2 in Canada, Patrese on pole. Mansell would have won the race without that last lap failure, which handed Nelson Piquet his 23rd and final world championship race victory.

The Williams charge continued, however, next time out in Mexico. Trying to match the FW14s, Senna crashed at the fearsome Peraltada as Patrese again beat Mansell to pole. The McLaren finished the race third, 57 seconds behind winner Patrese, who led a Williams 1-2.

By mid-season Williams had the fastest car. With seven rounds to go Mansell was just eight points behind Senna, and Williams had overtaken McLaren in the constructors' table

"Unless we change our equipment pretty fast, we are going to have problems later in the season," warned Senna. It was only round six of 16.

Then Mansell hit his stride, reeling off three wins in the French, British and German Grands Prix. Remarkably, Senna ran out of fuel at both Silverstone and Hockenheim, thanks partly to inaccurate consumption readouts due to changes in fuel specification, though he did score points for fourth in Britain.

Suddenly, Senna's grip on the crown seemed rather less firm. "They are better than us at the moment as a package," said Senna at Silverstone, where McLaren brought five cars.

At several rounds Honda provided more than one specification of engine and Shell brought multiple fuels as the team tried to hold back the Williams-Renault-Elf combination.

But there can be little doubt that by mid-season Williams had the fastest car. With seven rounds to go Mansell was just eight points behind Senna, and Williams had overtaken McLaren in the constructors' table.

"We are waiting for new things, soon," said Senna at Hockenheim. "To catch the Williams we need a lot more than we are going to have and we need it fast because the championship is still open. The performance that the Williams-Renaults have right now, we can't compete with them."

Senna's pressure on McLaren and, in particular Honda, ramped up. He had enjoyed a special relationship with the Japanese manufacturer since his Lotus-Honda campaign in 1987. And Honda responded with an extensively revised V12 for August's Hungarian GP.

The Hungaroring weekend, which took place just days after the death of Honda founder Soichiro Honda, was a crucial one. Senna had not scored a pole since Monaco in May, but outperformed the Williams duo with a superb lap, 1.2s clear.

This was perhaps one of Senna's great unheralded qualifying performances, but he was also boosted by the new Honda engine's ability to rev to 14,800rpm in short bursts.

This perhaps helps to explain why, using supertimes, the McLaren MP4/6 comes out as the fastest car of 1991. Supertimes are based on the fastest single lap by each car at each race weekend, expressed as a percentage of the fastest single lap overall (100.000%) and averaged over the season. And that normally means qualifying rather than race pace.

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They normally give a reasonable representation of the relative speed of each team in a given year, but one weakness comes if a certain car or cars is able to be 'turned up' in qualifying. The almost unlimited boost used by the top turbo runners in the mid-1980s is an example of this, but the Honda V12 development could be considered a milder version.

The early-season performances, Senna's prowess over one lap and the later-spec Honda engine's ability to produce more power for shorter runs means the McLaren's qualifying record - and therefore its supertimes data - is better than its competitiveness in GPs.

Across the season the MP4/6 was 0.27% faster than the FW14 using supertimes, yet it could be argued that the Williams was the quicker car in the races from June's Canadian GP up to and including the Spanish GP at the end of September, before McLaren's developments put it on a more even footing for the final races in Japan and Australia.

That span covers 10 of the season's 16 races, and Williams won seven of them. Crucially, Senna won two of the three that got away, while McLaren won all six of the GPs in which Williams did not have a clear advantage. The final tally was 8-7 in McLaren's favour. Senna and McLaren clearly made more of what they had than Mansell and Williams.

The first of Senna's against-the-tide wins came in Hungary. He used that pole to narrowly hold off Patrese at the start of the race. Having chased Senna for 44 laps, Patrese moved aside for Mansell to attack the McLaren, but he couldn't breach the reigning world champion's defences and the rediscovered straightline speed of the Honda V12 either. Mansell's momentum had been checked.

"In general Ayrton was a little bit luckier on the reliability side, but at the end of the day he got the job done in a good way" Gerhard Berger

"The Williams were quicker than me today but I had the lead at the first corner and overtaking here is very difficult," said Senna. "Fortunately, I was quick down the straight so that Riccardo and Nigel were never quite close enough at the first corner.

"This was the first time since Monaco I felt I was going into a race I could win."

Senna and Alain Prost's Ferrari kept Williams off the front row at Spa, and Senna's luckiest victory of the season came the following day. Prost's engine caught fire early on, Mansell went out from the lead with electrical problems and Jean Alesi had a Ferrari engine failure while running ahead of Senna. As Senna grappled with gearbox issues, the Jordan of Andrea de Cesaris became a threat, only to blow its engine with three laps to go.

Those two August wins extended Senna's lead over Mansell to 22 points, got McLaren back ahead in the constructors' contest, and put the pressure on Williams. It meant that, realistically, it had to beat Senna in each of the final five remaining rounds, with Patrese between Mansell and the McLaren in at least one race thanks to the (then new) 10-6-4-3-2-1 scoring system.

Despite qualifying second to Senna at Monza, Mansell did what he needed to do in Italy. Having waved Patrese by, watched him attack and pass Senna then spin off with more gearbox gremlins, Mansell took the lead with 20 laps to go to keep his championship hopes alive.

He looked to be doing the same in Portugal after an aggressive start jumped him from fourth to second. Patrese played the team game and allowed Mansell past after leading the early stages, but then disaster struck.

Not for the last time, Williams was undone in the pitlane, Mansell's right-rear wheel parting company as he rejoined. Patrese won, but Senna finished second to extend his lead to 24 points with just 30 left on the table.

Mansell won brilliantly in the Spanish GP, famously going wheel-to-wheel with Senna, millimetres apart, though his pass on Berger for the lead probably flirted closer to disaster. A scrappy race in the damp from Senna, which included a dramatic spin out of the last corner, only netted fifth. It was perhaps the only 1991 race in which Senna gave points away, but he was still 16 ahead.

Outperforming McLaren on Honda's home ground at Suzuka was always going to be tough, as underlined by Berger leading Senna in qualifying. Mansell was 0.222s off pole in third, nearly 2s clear of Patrese. Senna then allowed Berger to escape in the early stages of the Japanese GP as he frustrated Mansell's attempts to get by.

When Mansell ran wide at Turn 1 and deposited his Williams in the gravel, the title was Senna's. He handed Berger victory on the final lap, then won the shortest GP in world championship history in monsoon conditions at the Adelaide finale - "It wasn't a race at all, it was just a matter of staying on the circuit, it was impossible," said Senna - to finish the season with seven wins and a 24-point margin over Mansell.

"In general Ayrton was a little bit luckier on the reliability side, but at the end of the day he got the job done in a good way and he was world champion," says Berger, who finished fourth in the table, with less than half of Senna's total.

The title secured, Senna famously admitted at Suzuka that he had deliberately taken out Prost in the 1990 race, but also made the point that the 1991 contest had been a cleaner, more satisfactory one.

"It's been an exciting one for me," said Senna. "It was a sad championship in 1990. In 1991 we were able to have a clean championship. It was a technical and sporting championship and I hope it will be an example, not only for myself, but for everyone who is competing in F1."

It was also one in which Senna had scored almost every point his car would allow. A harsh critic could argue that Senna's unusual throttle-blipping driving style contributed to his running out of fuel in Britain and Germany - Berger ran out after the line - but really it was only in the Spanish GP that Senna gave points away, finishing fifth when he should have been second or third.

He was also key to pushing McLaren and Honda forward behind the scenes while maximising the machinery he had at any given event.

In 1988 Senna won the world title on dropped scores - having scored fewer overall points than team-mate Prost, with no other team remotely competitive - and his 1990 crown will forever be tarnished by the Suzuka crash. But his 1991 was brilliant - and relatively free of on-track controversy. Autocourse described Senna as a "more complete and rounded performer than ever before" in its drivers top 10, which placed Senna first. He needed some luck, some chinks in the Williams armoury, but exploited them superbly.

His legendary 1993 efforts against the vastly superior Williams-Renault are more famous but Senna's successful 1991 campaign, fighting off the rise of that very combination, stands comparison with that and should be regarded as one of the finest titles in F1 history.

1991 season at a glance

This piece is part of an Autosport magazine special on 1991 in the 14 January 2021 issue. If you would like Autosport magazine delivered to your door each week, subscribe today and never miss your weekly fix of motorsport.