World number one Novak Djokovic overcame a "strange" lengthy rain delay to beat American Taylor Fritz 6-3, 7-6 (7/5) to reach the third round of the Italian Open on Tuesday.
Title holder Djokovic waited three hours to finish off the match despite Fritz's efforts in the second set.
"It was a really strange match, to play in the rain, it was difficult," the Serb said.
"It possibly helped me because the play was slower, and he has a good serve. He played really well.
"In these circumstances, you don't know how much time it will go on for. If you have to eat, rest, or not. You have to do what feels best for you," he added.
Djokovic, 33, playing his second tournament since winning his ninth Australian Open in February, will play Cameron Norrie or Alejandro Davidovich for a place in the quarter-finals.
Elsewhere, Canadian Felix Auger-Aliassime beat last year's runner up Diego Schwartzman 6-1, 6-3 and will face either Federico Delbonis or David Goffin, who meet early on Wednesday.
Earlier, sixteenth seed Grigor Dimitrov crashed out in the first round when he was beaten in straight sets by Spanish qualifier Alejandro Davidovich Fokina.
The world number 48 saved two set points in the second set as he dismissed the 2014 semi-finalist Dimitrov 6-4, 7-6 (7/2) to win in one hour and 43 minutes.
Tenth seed Roberto Bautista Agut booked his place in the second round with a comfortable 6-3, 6-4 win over American Tommy Paul.
On the women's side, Argentinian Nadia Podoroska, ranked 44 in the world, assured herself of a second round meeting with Serena Williams, playing her first event since the Australian Open, when she came from a set down to beat German Laura Siegemund 2-6, 7-6 (7/3), 6-1.
Madison Keys won the battle of the Americans when she overcame Sloane Stephens 4-6, 6-2, 7-5.