Wawrinka was untouchable on his serve through two sets, not facing a break point until Bellucci broke him twice to take the third.
The Brazilian broke Wawrinka in the third game of the fourth, but the Swiss broke back to knot the set at 3-3. After holding at love for a 5-4 lead, Wawrinka had two match points against Bellucci's serve in the 10th game but couldn't convert either.
He grabbed the tiebreaker by the throat, however, and finished it off with a service winner after two hours and 36 minutes with the hands of the clock creeping toward 1 am.
"I was playing really well," Wawrinka said of his sparkling start. "I was really aggressive and serving really well.
"When you drop your level a little against Bellucci, it's tough. He starts to play better."
The tension seemed to get to Wawrinka at least briefly when he told one loud courtside fan to shut-up.
But he was able to get back on the attack.
"The fourth set I tried to focus on my game," he said. "I was more aggressive at the end of the match."
Wawrinka will face Slovenian Blaz Kavcic in the third round. Kavcic beat 30th-seeded Frenchman Jeremy Chardy 6-2, 7-6 (8/6), 6-3 in the only other men's second-round match of the day.