Defending champion Stan Wawrinka and Andy Murray had their backs to the wall before coming out fighting in the first round, while Kei Nishikori was among the seeds to win in straights sets at the French Open on Monday.
Wawrinka twice trailed by a set but recovered to beat Czech Lukas Rosol 6-4 1-6 6-3 3-6 6-4 following a delayed start at Roland Garros due to rain.
After such a dramatic start, there was also a thrilling finale on Court Philippe Chatrier on day two as Murray lost the first two sets against Radek Stepanek but was on the charge at 3-6 3-6 6-0 4-2 when play was suspended due to the light.
The second seed and the veteran Czech will return to complete that gripping match on Tuesday, just as Nishikori had to step back onto the court to finish off Simone Bolelli 6-1 7-5 6-3.
World number 11 Marin Cilic fell at the first hurdle with a defeat to qualifier Marco Trungelliti.
STAYING POWER CRUCIAL FOR STAN
Wawrinka was taken all the way by Rosol and the Swiss felt his stamina was the difference after he avoided becoming the first defending champion to lose in the first round of the French Open.
The two-time grand-slam champion said: "I think mentally I fought hard. At the middle of the third set up to the end, I was really tough with myself. I really tried to be good physically. I know that physically I'm stronger than he is, and I knew that he was going to decline a little bit. That's exactly what happened.
Wawrinka will now face Japanese world number 93 Taro Daniel in the third round.
FIFTY UP FOR NISHIKORI
Fifth seed Nishikori lost only two games on Monday as he completed a straight-sets victory over Italian Bolelli to take his tally of grand-slam wins to 50.
Andrey Kuznetsov is next up for the vibrant Japanese world number six, who is eager to show he can mix it with the best on the red dirt.
He said: "On clay, I think the biggest challenge is beating Rafa [Nadal] and Novak [Djokovic] and, you know, Andy [Murray], too. I think that's my next challenge."
CILIC SENT PACKING
Cilic is the highest-ranked player in the men's draw to be out of the second grand slam of the year after Argentine Trungelliti beat the 10th seed 7-6 (7-4) 3-6 6-4 6-2 on Court 2.
Croatia's Cilic was made to pay for 49 unforced errors by the 166-ranked Trungelliti, who recorded only his second victory at a grand slam.
The 2014 US Open champion Cilic has now lost in the first round of the French Open on three occasions.
FRENCHMEN FLY THE FLAG
All five Frenchman who completed their matches on day two were able to secure their passage into the next round.
The elegant Richard Gasquet saw off Thomaz Bellucci 6-1 6-3 6-5, while Jeremy Chardy got the better of Leonardo Mayer 6-4 3-6 6-4 6-2 and Adrian Mannarino beat Mikhail Kukushkin 6-4 2-6 6-2 6-4.
Gilles Simon and Mathias Bourgue were also able to book their place in the second round.