Fuel saving cost the McLaren Formula 1 team 50 seconds in the Russian Grand Prix and without it, the team would have matched Williams's pace, says racing director Eric Boullier.
Fernando Alonso finished sixth, one lap down, but was 52.829 seconds behind fourth-placed Valtteri Bottas at Sochi.
Boullier says that gap was entirely down to the Honda engine's fuel appetite compared to rival power units.
"We can see that we are the team that have a lot of fuel saving for obvious reasons," said Boullier.
"But with Fernando you could see towards the end of the race he was more than 1.2s faster [per lap].
"So without fuel saving we'd save another 50s which we would've had at the end of the race.
"If you look, we are with Williams [without fuel-saving] so it's the kind of progress we need to go [further].
"But that the pace was good and the drivers were happy with the car balance.
"Fernando had some fun."
Alonso's team-mate Jenson Button was 10th to give McLaren its first double-points finish since last year's Hungarian GP.
Boullier said McLaren's race pace was better than expected and a welcome tonic after it just missed out on Q3.
"We keep bringing performance and missing Q3 for one tenth was a bit of blow," he said.
"But it was a good surprise in the race because our race pace was better than expected."
Alonso was delighted with the result as he felt it was reward for the team's hard work of late.
"I feel happy," he said. "We deserve the points, finally, after some unlucky situations. The pace was very good.
"We've been lucky at the start, we recovered some places after the accidents, but then the car performed quite well and we didn't have any threat from behind.
"We had the fifth-fastest lap of the race so I think sixth position is what we deserve and I'm happy with the way everything is going.
"We seem more and more competitive every race, so let's hope from Barcelona and Monaco to get some more points."