Monte Carlo: Eight-time winner Rafael Nadal and four-time finalist Roger Federer will line up against a pair of underpowered hopefuls in the second round of the Monte Carlo Masters.
Nadal, who is working to return to his previous best on his longtime favourite surface, will open in the second round after a bye against British number two Aljaz Bedene.
The Slovenian-born world number 60 will face one of the toughest tests on clay when he takes on the Spaniard who dominated with consecutive trophies from 2005-12.
Nadal has never played Bedene, Federer is 3-0 over Garcia-Lopez as the pair meet for the first time on clay.
Bedene booked his spot against Nadal as he defeated Czech Lukas Rosol 6-2, 6-3 on Monday.
Spaniard Guillermo Garcia-Lopez made it past Brazil's Thomaz Bellucci 7-5, 6-1 to next face third seed Federer, who is set to play his first match in more than two months after a knee procedure.
Nadal is looking for his first title on any surface since last summer and will willingly make 57th-ranked, Slovenia-born Bedene his first victim of the week in the principality.
Federer most recently lost a Monte Carlo final two years ago against compatriot Stan Wawrinka.
Bedene appears ready to take up his challenge against the mighty Nadal. "I'm playing well, at the moment I'm enjoying playing tennis. It's going to be against Rafa, who I respect. He's one of the best clay-courters.
"It's going to be fun, definitely if I bring my best tennis. I'm not the favourite, but I stand a chance. It's never a good time to play someone like him. But if I can pick any, this is the time."
Nadal has been struggling to emerge from a long-running crisis of confidence on court, with the 29-year-old now believing that he is back to his normal clay level.
Two French seeds gave the home public what they wanted in the first round, with number nine Richard Gasquet defeating Spain's Nicolas Almagro 6-4, 6-0 and 13th-seeded Gael Monfils recovering form 2-5 down in the opening set to defeat Gilles Muller of Luxembourg 7-5, 6-0.
Spanish 14th seed Roberto Bautista Agut advanced past compatriot Albert Ramos-Vinolas 6-4, 7-6 (7/4).
"It was just a break down, 5-2, one break on clay," a relaxed Monfils said.
"Of course, on hard courts it would have been more complicated. But on clay...
"During the first set I didn't return well, but I was able to improve, I played quite well.
"Little by little I was able to get used to the court and I was able to play a bit higher and find the right angles to make him move.
"I played a solid match - not a great match, but it was a solid one."
German teenager Alexander Zverev continued to impress after holding a match point against Nadal last month at Indian Wells, with the 18-year-old winning his debut match in the principality over longtime junior rival Andrey Rublev 6-1, 6-3.
That quick victory in one hour lines up the 54th-ranked Zverev against former Monte Carlo finalist David Ferrer in the second round.
"It's going to be a great match, a great test for me," Zverev said.
"He's one of the toughest competitors on clay. He's been playing great on clay his whole career.
"He's been a solid top-10 player for 10 years now. It's going to be a great match. I'm looking forward to it."
In other results, Pierre-Hugues Herbert of France beat Guido Pella 6-3, 6-4 to next take on second seed Andy Murray.
Austrian 12th seed Dominic Thiem earned a comeback win over Jan-Lennard Struff 1-6, 6-3, 6-4 while Canadian tenth seed Milos Raonic put out Marco Cecchinato 6-3, 7-5.
Bulgarian Grigor Dimitrov defeated Filip Krajinovic 6-3, 6-2 and Pablo Carreno Busta stopped Frenchman Stephane Robert 6-3, 6-1.