Jannik Sinner survives the Tomas Martin Etcheverry test at the Shanghai Masters

World number one Jannik Sinner recovered from a deficit to claim a hard-fought victory against Tomas Martin Etcheverry in the third round of the Shanghai Masters.

The Italian top seed was pushed to the end before winning 6-7 (3-7), 6-4, 6-2 in two hours and 38 minutes.

In the decider, Sinner held serve through an 11-minute sixth game to take a 4-2 lead before winning the next two games to secure the victory.

“It became stressful because if I lost the game 2-3 and he made the break, we would be even again,” Sinner said.

“Sometimes you have to wait for your chances, which I did, and at the same time try to stay mentally calm and that was the key today.”

Sinner has won six titles this year, including two Grand Slams, but is playing amid the World Anti-Doping Agency appealing the decision to clear him of guilt after he twice tested positive for a banned substance.

Leading 6-5 in the first set, he failed to get two break points before his Argentine opponent, who impressed with big serve and strong play, won the tiebreak.

Sinner won the fifth game of the second round on Etcheverry's serve with a sizzling forehand down the line, but the world number 37 responded with a breakback with an equally beautiful crosscourt forehand.

The Italian secured a second straight break and confidently served out the set to level the game before securing the deciding set and progressing to the round of 16 where he will face either Spaniard Roberto Carballes Baena or American Ben Shelton.

“It was a very tough game physically but also mentally, so I'm very happy that I got through it and let's see what comes next,” Sinner added.

Daniil Medvedev also managed to beat Matteo Arnaldi 5:7, 6:4, 6:4 in two hours and 44 minutes.

Medvedev got the decisive break in the ninth game of the deciding set before serving for the match and will play either Stefanos Tsitsipas or Alexandre Muller in the round of 16.

“It was a very tough, very close game,” said Medvedev. “I actually felt like tennis was fun there. I felt like I was probably the better player in the first set and had more opportunities. I didn't manage to (win) it and ended up playing a bad game.” Sentence.

“In the other sets I thought it was closer, maybe he was even ahead in some moments. But that's why tennis is crazy, you can win when you don't expect it and lose when you expect a win. That's why I'm looking forward to being back here in two days.

Because of the rain, games on the outdoor courts were canceled for the second time in a row; games were only possible under the roof of the main stadium.