The Mercedes Formula 1 team was left feeling “bittersweet” as Lewis Hamilton sealed his fifth world championship in what was a “painful” Mexican Grand Prix.

Hamilton made a fast start to challenge for the lead on the run to Turn 1 as he gained a place to run second during the early stages in Mexico City.

But the Briton was forced onto a two-stop strategy after struggling with excessive tyre wear which hampered his race pace, while Valtteri Bottas pitted three times as he finished a lap down on race-winner Max Verstappen in fifth.

Ultimately a fourth-place finish was enough to see Hamilton crowned a five-time world champion, but Mercedes team boss Toto Wolff said his squad has a lot of work to do following a “very bad race”.

“It’s a fantastic title and I’m so happy for Lewis and the team,” Wolff told Sky Sports F1.

“It’s all a bit bittersweet, we had a very bad race which we need to understand and in our mind that plays such a big role but we should be happy about the championship.”

Hamilton described the race as “horrible” as he scored his worst finish of the season since coming fifth in June’s Canadian Grand Prix.

“It was a horrible race,” he explained. “I had a great start and was really working my way up but then I don’t know what happened after that.

“We were struggling, both myself and Valtteri. I was trying to hold on and bring the car home.”

Mercedes F1 technical chief James Allison admitted the team struggled to fully savour the moment given its “painful” performance at the Autodromo Hermanos Rodriquez.

“It has been a topsy-turvy sort of weekend,” Allison told Sky Sports F1. “We have to remember that what we have achieved today we have achieved as the result of a whole year of effort.

“Today was painful, painful indeed. You have to remind yourself to be happy when you just took a bit of a pasting like that.

“But the overall achievement is magnificent and Lewis’ driving this year has been peerless so we have to be happy.

“It means everything to him,” he added. “He is utterly focused on this. He’s done five now and yet it might as well be his first.

“He comes to each weekend burning with the desire to put the car in front of the others and I’m sure he will be the same next year as well. This is how he defines himself and he’s not happy until he’s done it.”