Lewis Hamilton called his narrow 0.7s victory over Max Verstappen at the Bahrain Grand Prix one of the hardest races in recent memory.
Hamilton held off a charging Verstappen to win the season opener. The closing stages saw Verstappen reeling Hamilton in and, briefly, get ahead with four laps left.
However, Verstappen had passed Hamilton with all four wheels off the track and had to give the position back immediately. Hamilton was able to stay in front for the final laps to claim the 96th victory of his career.
"What a difficult race that was," Hamilton said after the race. "They've had an amazing performance all weekend. So it would take something really special."
Hamilton's win required him to drive to the finish on old hard tyres, while Verstappen reeled him in on fresher medium tyres.
Hamilton said: "We stopped for that last stint and were trying to find the right balance between not pushing too much and having tyres that were alive at the end of the race It was difficult and Max was all over me right at the end, but we just about managed to hold him off.
"It was one of the hardest races I've had for a while, so I'm really grateful for it. Massively thankful to the men and women back at the factory and the guys, and here also, for continuously pushing the boundaries and never giving up even if we did feel we were behind."
The tense battle at the front seemed to confirm preseason expectations that 2021 could be a close fight between Hamilton and Verstappen. Hamilton said he will need to be at his best to win an eighth world championship this year.
When asked if he was looking forward to the season, Hamilton said: "I definitely am. Each year, they're talking about when you have hit your peak and I am trying to make sure ... well I think timing is everything, I think I'm probably at that, and Max is really doing well at the moment too.
"It's going to take everything and more for us to put in performances like this. We love the challenge and I love the challenge; I still love what I do."