The 22-year-old World Number One needed three hours and 42 minutes to see off his Davis Cup teammate Berrettini, the former World number Six and the 2021 finalist at Wimbledon.
“First of all, we are very good friends,” Sinner said.
“We played the Davis Cup together and we practise together, so it is very tough we had to face [each other] in the second round in such an important tournament.
“Today was a very high-level match.
“In three tie-breaks I got a little bit lucky and I take it for today.
“I knew I had to raise my level.
“He played the final here and is a grass-court specialist.
“I was looking forward to it and it was a challenge to come on court and I am very happy with how I handled the situation.
“There were some ups and downs, which is normal in a five-set [match], but I am happy.”
ANSA