World No. 1 Novak Djokovic reached his 10th French Open semi-final but suffered an injury scare before beating Spain's Pablo Carreno Busta 4-6 6-2 6-3 6-4 on Thursday (NZ time).
A month after being defaulted for striking a line judge with a ball while playing Carreno Busta in the US Open fourth round, the 33-year-old Serbian found himself in trouble once again.
This time it was nothing more sinister than pains in his neck and arm as Djokovic lost the opening set to the 17th seed - the first one he has dropped in the tournament.
Djokovic looked flat and had to save break points early in the second set before raising his game to level the match.
Then it looked plain sailing when he led 3-0 in the third set before a dip allowed Carreno Busta back but Djokovic saved a break point at 3-3 before pulling away.
Djokovic, bidding for a second French Open crown, produced several loud roars as he tried to fire himself up.
Carreno Busta hung on gamely but Djokovic was superior in the big moments and one break in the fourth was enough to set up a semi-final clash with Greek Stefanos Tsitsipas.
Earlier, Tsitsipas reached his second Grand Slam semi-final as he raised his game after a slow start to defeat Russian Andrey Rublev 7-5 6-2 6-3.
Before the quarter-final on Court Philippe Chatrier, the 13th-seeded Rublev had won both previous tour-level meetings against fellow 22-year-old Tsitsipas with their last encounter less than two weeks ago in the final in Hamburg.
The Russian looked set to keep his record intact as he served for the first set at 5-4 but Tsitsipas, who also reached the semi-finals at last year's Australian Open, then won three straight games to take the opener.
Tsitsipas did not look back from there and broke his opponent three more times in the next two sets.