Murray`s defeat at Queen's ended his 14-match winning streak on grass and his 10-match unbeaten run at Queen`s Club, a warm-up event to Wimbledon.
There were several top-notch rallies and Schiavone pulled a few tricks from her bag, threatening in the second set.
Nadal is bidding to become the first player in the Open era to win 10 titles at any Grand Slam event, with a spectacular return to form in 2017 once more marking the Spaniard out as this year`s Roland Garros favourite.
Kerber became first top seed to lose opening round, even as Kvitova makes emotional winning return.
Before this year, the earliest exits suffered by a top seed in Paris came in the second round -- Justine Henin in 2004 and Serena Williams in 2014.
Serena Williams may be missing from this year's French Open, but big sister Venus is still going strong and marks her Roland Garros 20th anniversary on Sunday.
The 32-year-old Tsonga will open his campaign at Roland Garros -- where he twice reached the semi-finals -- against Argentine Renzo Olivo, a first round casualty in Lyon.
Zverev, 29, had been bidding for his maiden tour title the 33rd-ranked player`s first final appearance in seven years.
The 17-year-old Abhimanyu tamed the fighting Japanese 6-1 4-6 6-1 in two hours and 15 minutes at court number six of Roland Garros.
The 20-year-old Alexander Zverev beat Novak Djokovic to win the Italian Open last Sunday, while the 23-year-old Dominic Thiem also impressed in the tournament, defeating Nadal.
American eight-times grand slam champion Agassi, 47, has taken on a coaching role for the first time since ending his glittering playing career in 2006.
Nadal, who was forced to withdraw from last year's Roland Garros with a wrist injury after two rounds, has already reached the magical 10 titles number this year at the claycourt events in Monte Carlo and Barcelona.
Kvitova, who said this week she was set to play at Wimbledon where she has twice won the title, has not played competitively since the attack, which left her with serious injuries to her left playing hand.
World number one Andy Murray is seeded to face 2015 champion Stan Wawrinka in the last four.
The Spanish star withdrew from the 2016 tournament with a left wrist injury on the eve of his third round match.
Simona Halep, the 2014 runner-up, established herself as arguably the leading challenger by winning the Madrid Open before reaching the Rome final, but an ankle injury has cast doubt over her status.