Halep progresses
Reigning champion Simona Halep started her French Open title defence with an ultimately comfortable victory on Tuesday despite a second-set blip against Australian Ajla Tomljanovic.
The Romanian was pegged back on Court Philippe Chatrier but raced through the decider to win 6-2, 3-6, 6-1.
Halep, seeded third, will face Poland's Magda Linette in the second round.
The 27-year-old, who won her first grand slam title in Paris last year after three previous final defeats, looked to be in total control after taking the first set in less than half an hour.
Tomljanovic, who reached the last 16 in 2014, hit back though to level the match.
But Halep, like world No 1 Naomi Osaka in the preceding match on the show court, avoided an upset by easing through the third set despite being broken when initially serving for the match.
Halep finished an accomplished display with 19 winners and 22 unforced errors.
Del Potro find his range
Juan Martin del Potro recovered from losing the first set to cruise through the next three and book his place in the second round with a 3-6, 6-2, 6-1, 6-4 over Nicolas Jarry on Tuesday.
The eighth seed, who only returned to action after a knee injury earlier this month, has shown good form on clay in the last two years, reaching the 2018 semi-finals at Roland Garros before losing to Rafael Nadal.
The Argentine - the 2009 US Open champion - will face either Japan's Yoshihito Nishioka or American Mackenzie McDonald in the second round.
Fognini wins battle of the Italians
Monte Carlo Masters champion Fabio Fognini booked his place in the second round with a 6-3, 6-0, 3-6, 6-3 win over fellow Italian Andreas Seppi.
Fognini won his first Masters 1000 title in Monaco in the build-up to the French Open and displayed similarly good form to overcome a potentially tricky encounter against former world No18 Seppi.
Fognini will take on the in-form Federico Delbonis, who last week reached the semi-finals in Geneva. The Argentine world No 75 also progressed in four sets, defeating Spanish veteran Guillermo Garcia-Lopez 6-1, 3-6, 6-3, 6-2.
Fritz blitzes Tomic
American Taylor Fritz needed just one hour and 24 minutes to defeat Australian Bernard Tomic 6-1, 6-4, 6-1 to book his place in the second round.
Tomic, who has only won two matches on clay, continued his poor run of form and was no match for Fritz, who broke the world No 84's serve twice in the first two sets and three times in the third.
Fritz, the world No 42, will face either Spain's Roberto Bautista Agut or American Steve Johnson in the second round.
Also through with an emphatic performance is local qualifier Elliot Benchetrit, who thrashed Britain's Cameron Norrie 6-3, 6-0, 6-2, taking just three minutes longer than Fritz to claim his own victory.
Britain does have at least one player through to the men's singles second round after Kyle Edmund swiftly wrapped up his marathon five-set match with Jeremy Chardy, winning both games to complete a 7-6, 5-7, 6-4, 4-6, 7-5 win.
Zverev sweats it out
German fifth seed Alexander Zverev, a quarter-finalist in 2018, battled past Australia's John Millman 7-6, 6-3, 2-6, 6-7, 6-3 in a shade over four hours.
The champion in Geneva last weekend fired 57 winners past world No 56 Millman who stunned Roger Federer at the US Open last year.
However, he also committed 73 unforced errors on a blustery day in the French capital.
"John is a tough player so I knew it would be difficult today," said Zverev, bidding to become the first German man to win the Roland Garros title since Henner Henkel in 1937.
Next up for Zverev is Swedish qualifier Mikael Ymer, the world No 148 of Ethiopian origin, who marked his grand slam debut with a 6-0, 6-3, 7-6 win over Slovenia's Blaz Rola.
Strong debut from Andreescu
Canada's Bianca Andreescu, the surprise champion at Indian Wells, marked her Roland Garros debut by beating Marie Bouzkova of the Czech Republic 5-7, 6-4, 6-4.
The 18-year-old, playing for the first time since Miami after suffering a shoulder injury, hit 58 winners and 60 unforced errors.
Karlovic wins oldest match
Ivo Karlovic made a mockery of his 40 years to beat relative spring chicken, 37-year-old Feliciano Lopez, in the oldest ever men's match-up at Roland Garros.
Croatian Karlovic, the tallest player on the tour at 6ft 11in (2.11m), defeated Lopez 7-6, 7-5, 6-7, 7-5.
He is the oldest man to win a grand slam match since Ken Rosewall in 1978.
Later Tuesday, defending champion Simona Halep faces Australia's Ajla Tomljanovic, the world No 47, who reached the fourth round in 2014.
