Mercedes executive director Toto Wolff "hated" Sunday's Mexican Grand Prix but was eventually able to revel in "ultimate happiness" following Lewis Hamilton's world championship success.

Hamilton and Ferrari title rival Sebastian Vettel clashed on the opening lap, forcing both men to pit with damage to their respective cars.

Having rejoined at the back of the field, Hamilton guided his Mercedes to ninth, and Vettel could not secure the win he needed to keep his faint title hopes alive.

Although it was soon apparent that Vettel had hardly any chance of winning the race to keep the pressure on Hamilton, Mercedes and their driver initially struggled to recover after the dramatic start.

"I hated every bit of that race," Wolff told Sky Sports. "It was really bad and too long.

"We were rattled after the beginning and the crash. [Lewis was thinking:] 'Is Sebastian still in the race?' We relayed the situation to him and, after, he settled."

Trailing by 66 points, Vettel required a hugely improbable turnaround to overturn Hamilton in the final three races, but Wolff was still relieved to get the job done early.

"You have this massive gap in points and people say it's done, but it's not," he said. "It's racing."

On the first-lap collision, he added: "The championship is at stake. In normal conditions I think it would have been a penalty, but this is a decider."

Wolff also raised a laugh when he said: "I saw Lewis in the back. I rarely hug half-naked, sweaty men but it was still a good feeling. It's ultimate happiness."

Technical director James Allison added his delight at Hamilton securing a fourth world title.

"This was definitely an ugly race," he said. "We left the last race buoyed by the constructors' championship, but we're very much aware that this is the one that counts.

"After the season we've just had, it's hard to imagine a champion who deserves it more than Lewis does.

"This has been the most difficult and exciting season that there's been in years and Lewis has driven it to perfection."