Sixth seed Dominic Thiem has traded blows with American Steve Johnson for more than two hours under darkening Roland Garros skies before winning 6-1 7-6 (7-4) 6-3 in an enthralling contest.

After a quickfire first set dominated by the Austrian, 25th seed Johnson fought back in the second on Friday, earning two set points in the 10th game that he failed to convert.

Thiem, one of the dark horses to win the tournament after beating favourite Rafa Nadal in straight sets in Rome earlier this month, stepped up his heavy groundstroke game in the third set.

Mixing power with precision throughout, the Austrian closed out the match in a shade over two hours with an unreturned cross-court backhand volley.

Milos Raonic reached the last 16 after Spanish veteran Guillermo Garcia-Lopez retired at the start of the second set.

Fifth-seeded Raonic cruised through the first set 6-1 in 21 minutes and led 1-0 in the second when Garcia-Lopez retired at the changeover with a quad injury.

Canadian Raonic will face another Spaniard in the fourth round after Pablo Carreno Busta upset the 11th-seeded Grigor Dimitrov in straight sets.

The 20th-seeded Carreno Busta was too consistent for Bulgarian Dimitrov in a 7-5 6-3 6-4 victory.

Spain’s contingent in the round of 16 swelled with Roberto Bautista Agut too good for Czech Jiri Vesely.

The 17th-seeded Bautista Agut broke Vesely on six occasions in a 6-3 6-4 6-3 win.

Earlier, Belgian David Goffin was forced to retire from his third-round encounter against Argentine Horacio Zeballos after slipping and hurting his ankle.

The world No.12 was leading 5-4 in the first set when he fell heavily at the back of the court as he chased down a deep forehand from Zeballos.

Goffin received treatment but the injury was too severe to continue and he was forced to concede the match.