"It was very difficult. We're good friends off the court, but it was a bit of a challenge to overcome," Sinner said of Darderi, as quoted by ATP.
The world No. 2 played dominantly after battling cramps against Eliot Spizzirri in the previous round -- a match in which he later admitted he was "lucky" the roof closed in time.
Sinner survived a tense finale against Darderi, as his momentum and fitness were threatened to decline.
"In the third set, I had a couple of break chances , but I couldn't capitalize on them. Then I got really nervous, so I'm really happy to close it out in three sets," said Sinner.
In his first head-to-head meeting with Darderi, Sinner dominated from the back with perfect timing and sharp serving.
Darderi threatened late in the third set when he produced an aggressive attack from the baseline to earn four break points at 4-4 and lead 2/0 in the tie-break.
However, Sinner closed the opportunity emphatically, winning seven consecutive points to complete the victory.
