British number one Kyle Edmund needed just two games to book his place in the French Open second round as he wrapped up victory in his interrupted match against Jeremy Chardy.
The pair had resumed at 5-5 in the fifth set after bad light stopped play on Monday.
Edmund won 7-6 (7-1) 5-7 6-4 4-6 7-5.
But British number two Cameron Norrie lost 6-3 6-0 6-2 to French qualifier Elliot Benchetrit after an erratic display.
Compatriot Dan Evans begins his campaign later on Tuesday against Spaniard Fernando Verdasco.
Edmund made to battle in patchy performance
Edmund has dropped to 30th in the rankings, down from 14th at the start of the year, after five successive defeats on the clay which he once described as his preferred surface.
His form on the red dirt this year has been a far cry from 12 months ago.
After losing in the third round at Roland Garros, when he was knocked out by clay-court expert Fabio Fognini in a five-setter, he was able to reflect on a swing in which he reached his first ATP final in Marrakech and beat 12-time Grand Slam champion Novak Djokovic in Madrid.
This year he went into the clay Grand Slam having only beaten 63rd-ranked Frenchman Ugo Humbert in Marrakech, although his defeats did come against players with plenty of pedigree – Fognini, Jo-Wilfried Tsonga, Diego Schwartzman and Fernando Verdasco.
The Yorkshireman’s attitude to his form has been rather stoic, saying there was no need to panic because he knew he was a good player.
He showed glimpses of it on Court One throughout the opening set – finishing in style with a dominant tie-break – but his feathers started to get ruffled by Chardy, who was buoyed by the home crowd.
The Frenchman capitalised on a fourth break point when Edmund double-faulted in the second set and added a sucker-punch with another break late on.
Edmund’s unforced errors’ count increased to 34 in the third set as he let a 4-2 lead slip but he recovered, showing guile and composure to snatch it back.
The light began to fade in Paris and the danger of play being suspended grew as Chardy broke twice in the fourth and Edmund could not prevent it going to a gruelling decider despite a spirited late comeback.
The British number one then crucially held off two break points at 2-2 in the fifth before the match was suspended at 5-5.
Edmund came out fired up when it resumed on Tuesday, taking just seven minutes to first hold serve then break to claim victory and book a meeting with Uruguyan world number 47 Pablo Cuevas.
The British 28th seed has now made it past the opening round in all five of his appearances in Paris.
Norrie out after dismal display
British number two Norrie’s hopes of joining Edmund in round two were ended when he was out-powered by world number 273 Benchetrit.
The 23-year-old Briton, ranked 49th, looked devoid of belief and failed to muster a break point until the final game, losing serve six times.
Benchetrit, 20, needed only one hour 27 minutes to earn his first Grand Slam main-draw win, taking control by claiming nine games in a row from the back end of the first set.
By that time Benchetrit was already causing problems for the Briton with his hefty serve and potent forehand.
The Frenchman ended up hitting 29 winners as Norrie produced 33 unforced errors in a dismal display.
