Mystery behind Ricciardo's horror F1 comeback

It was not the welcome back to Formula 1 that Daniel Ricciardo would have hoped for after a disastrous United States Grand Prix saw him finish dead last.

In his return race after breaking his hand at the Dutch Grand Prix, Ricciardo crossed the line in 17th — but was classified 15th after Lewis Hamilton and Charles Leclerc were disqualified.

After starting 15th on the grid, Ricciardo moved up five positions early and was as high as seventh as a result of some pit stops and early retirements around him.

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However, Ricciardo soon began to slip back through the field as his one-stop strategy failed to break open the race.

Ricciardo finished seven places behind his AlphaTauri teammate Yuki Tsunoda and last of the drivers who survived the race.

Abandoning their unsuccessful one-stop strategy, Ricciardo came in for a late pit stop and changed to soft tyres.

"The one-stop strategy wasn't working. He's put the soft tyres on and just set the fastest lap of the race," former driver Martin Brundle said in commentary for Sky Sports.

On-board footage of the stop also showed AlphaTauri's pit crew removing a large piece of debris from the front end of Ricciardo's car.

"We had damage to the front brake duct. We don't think we touched anyone or anything, so we'll have to understand why that happened," AlphaTauri later communicated to Ricciardo over the team radio.

"Texas hasn't been too kind," Ricciardo said afterwards.

"At the start, we were doing well with our plan, but the problem was once the cars with blue flags came up behind us, we lost too much.

"We seemed to struggle in traffic and then we picked up some damage later on, so after that, we lacked pace.

"On the medium compound, we were doing the same lap times as Yuki, but because I was on a one-stop, there was a bit more tyre management going on for me. Physically, I feel better today than yesterday, so the sprint race was a good warmup for the Grand Prix.

"I got more race mileage, and there's a lot to learn from this race, so now it's full attack for Mexico."

AlphaTauri's technical director Jody Egginton confirmed that Ricciardo's pace dropped off because of the damage sustained to the car.

"Daniel's race was more difficult later on, but he also put in a very well-managed first stint, opening up strategy options for him," he said.

"However, soon after his first stop, he picked up damage to brake duct parts, resulting in a significant loss of aero load and aero balance, meaning he was unable to run at the pace he was capable of and fell back into the chasing pack.

"Later on, we took the gamble to stop and try to resolve the issue in case of a late race safety car. Although we improved the car balance at the stop, the race finished without incidents, providing no opportunity to move him forward."

The switch to soft tyres helped Ricciardo set the fastest lap before Tsunoda swooped in on his last lap of the race.

Only drivers that finish in the top 10 can claim the bonus point for the fastest lap.

Promoted to eighth place with the disqualifications, Tsunoda picked up four championship points as well as an additional point.