Tsitsipas says 'relaxation' key to improved serve after win over Thiem

World number five Stefanos Tsitsipas landed 39 straight first serves en route to claiming a 3-6 6-1 7-6(5) comeback win over Dominic Thiem at the Madrid Open, with the Greek crediting his focus and relaxation for his near-perfect serving performance.

Tsitsipas looked in danger of falling in his first match of the tournament on Saturday, but he found a way back into it by dominating the second set and then clinching the tie-break in the decider.

The 24-year-old ended with a first serve percentage of 79 per cent, significantly higher than the 57 per cent he managed in his straight sets defeat to Carlos Alcaraz in last week's Barcelona Open final.

"That's fantastic, 39 is a lot," Tsitsipas said of his streak.

"That's a positive mark for me. I think I just owe it all to fluidity and just being relaxed on my serve... I think it's just pure relaxation and focus."

Tsitsipas also praised former US Open champion Thiem for turning the two-hour, 19-minute encounter into a physically demanding contest.

"I'm in a way happy that we were able to show that kind of tennis... Today sort of showed what kind of intensity two guys that play single-hand backhands can bring to tennis," Tsitsipas said.

"I'm happy I got away with a win. Things weren't easy at the very end but I just kept fighting... The third set it was just pure fight. He's not someone that's going to give up and he hates even giving the slightest to you in terms of free points."

Tsitsipas will next meet Argentine Sebastian Baez, who beat American Marcos Giron 3-6 6-3 6-4.