Still reeling from knee surgeries, former champion Stan Wawrinka has lost a five-set battle to Guillermo Garcia-Lopez in the first round of the French Open.
Last year's finalist lasted three-and-a-half hours before bowing out with a 6-2 3-6 4-6 7-6 (7-5) 6-3 loss to the 67th-ranked Spaniard.
Reigning champion Rafael Nadal was two sets up in his clash against Simone Bolelli when rain stopped play.
The world No.1 and 10-time champion will resume on Tuesday at 6-4 6-3 0-3 against the Italian.
Returning to the place where he claimed the second of his three grand slam titles did not help Wawrinka shake off his poor form. The Swiss player, No.30 in the world, looked a shadow of the player who won the title in Paris three years ago, struggling with his serve and hitting 72 unforced errors.
"There is no frustration, it's just tough," Wawrinka said following a result which will see him fall from No.30 in the world to outside the top 250. "But I'm on the right way. It was very close today."
Garcia-Lopez had already upset Wawrinka in the first round at Roland Garros when they met in Paris four years ago. He will next play Karen Khachanov of Russia.
The pair were joined in the second round by former champion Novak Djokovic, who advanced with a 6-3 6-4 6-4 win over qualifier Rogerio Dutra Silva of Brazil.
"He's a fighter. It was a good test for the first match," Djokovic said.
The 2016 Roland Garros champion said he felt he was beginning to play better and free of pain after "a long 12 months". This year is the first that Djokovic has not won a tour-level title prior to the French Open.
Djokovic faces Spain's unseeded Jaume Munar in the second round.
Third seed Dominic Thiem was too strong for Ilya Ivashka of Belarus, winning 6-2 6-4 6-1 while 13th seed Roberto Bautista-Agut moved through in five sets over Denis Istomin.
Elsewhere, rising Greek teen Stefanos Tsitsipas advanced at the expense of Carlos Taberner in four sets, while there were also wins for Benoit Paire, Khachanov, Cameron Norrie and Dusan Lajovic.
Seeds Sam Querrey, Diego Schwartzman and Richard Gasquet also advanced alongside Frenchman Gilles Simon.
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