Daniel Ricciardo's tyres 'ran out of steam' in Singapore GP chase

Ricciardo's late pitstop for fresh super-soft tyres gave him 13 laps to close down a 25.449-second gap to leader Nico Rosberg, whose Mercedes team had to leave him out on old softs because the Australian's stunning out-lap removed the possibility for Rosberg to pit and keep the lead.

With five laps remaining Ricciardo had closed to within 5.2s of Rosberg, only to miss out by 0.448s come the chequered flag.

Asked whether Ricciardo and Red Bull could have done any more, Horner said: "I don't think so.

"Nico had a very strong weekend, he had a bit too much for us in qualifying, and in the race we tried everything we could.

"I think the intention was for Nico to cover us, but we thwarted that at the last minute because Daniel's out-lap was so stonkingly strong - together with a fast pitstop. We were within the undercut.

"Having run the maths quickly, it looked like we'd catch him within a lap or two of the end.

"But having hit his tyres pretty hard at the beginning of the stint, they then started to run out of steam a little bit towards the end of the stint.

"Whilst Daniel did a fantastic job to close Nico down over the last laps, they had just left enough in hand to keep a margin until the chequered flag.

"To get within half a second in two hours [the elapsed race time] was a great performance, but it just wasn't quite enough."

Ricciardo conceded himself the tyres "were a little bit dead" at the end of the race, leaving him to endure his fourth runner-up finish this year, and third in the last four races.

It would appear Ricciardo's best shot at a win this season is now behind him, with many believing before the race the Marina Bay street circuit to be a Red Bull track.

Horner recognises it is now likely to take something extraordinary for his team to score another win this season to add to Max Verstappen's triumph in Spain.

"We got pretty close, within half a second, and we beat one of the Mercedes fair and square," added Horner.

"Hopefully the opportunities will present themselves over the next six races, but Mercedes have been so strong at every venue that it's going to rely on something different happening - weather, conditions, tyre deg, something like that."