Novak Djokovic acknowledged he had to change his approach after facing a first-set blitz from Thomaz Bellucci during his hard-fought three-set win at the Internazionali d'Italia on Thursday.
World number one Djokovic was forced to dig deep, recovering from a first-set bagel to triumph 0-6 6-3 6-2 victory.
Djokovic set up a quarter-final clash with Rafael Nadal with the win, but admitted he was not always sure of making his 10th successive quarter-final at the ATP Tour tournament.
"After the first set I had to change. First set was a complete Bellucci storm, and I was blown away from the court," Djokovic said.
"Fortunately the matches are played in best of three, so I had another opportunity to come back and to restart, which I did."
Djokovic held serve in the first game of the second set and celebrated what was to that point a rare success in the match.
The Serb said winning that game was the turning point of the match and fuelled his belief that he could overcome his sluggish start.
"The crucial game was the first game of the second set where I held my serve, and then I felt that things started to go my way as I tactically changed certain things, started to change the pace, get him on the move from one corner to another, with a little bit of a shorter and longer variety of balls. And it worked well," Djokovic said.
"Tomorrow is a big challenge playing against Rafa. The fact that I played against a left-handed player today hopefully will get myself positioned and prepared well for the next match.
"I've played him in Rome several times ... I have watched his match. I'm going to try to get myself ready. I'm hoping I can start better than I did today."