Novak Djokovic overcame a first-set blip to beat Russian Karen Khachanov 4-6 7-6(0) 6-2 6-4 and reach the French Open semi-finals on Tuesday, staying on course for a record-breaking 23rd men's singles Grand Slam title.

The twice Roland Garros champion could not find a weakness in the 11th-seeded Khachanov's serve at first, but once he took the second set tiebreak there was no looking back for the Serbian.

He will be closely watching Tuesday's night match between world number one Carlos Alcaraz and fifth seed Stefanos Tsitsipas, whose winner will be the last man standing between him and a seventh French Open final.

On a court Philippe Chatrier gradually being covered by the shade, the 36-year-old did not have a single break opportunity and looked a tad slow in the opening set, but his metronomic game eventually clicked and there was little Khachanov could do to top his opponent's march into the last four.

Khachanov stole Djokovic's serve to lead 3-2 and, although the world number three threatened in a 10-minute ninth game, the Russian held and went on to pocket the set.

There were no break points in the second set but Khachanov started to struggle and paid for his efforts, failing to score a point in the tiebreak as Djokovic levelled the contest.

Djokovic got the early break thanks to a netcord in the third and stole Khachanov's serve again to move one set from victory with apparent ease.

The Serbian broke again early in the fourth set, only to serve a double fault that allowed Khachanov to level for 4-4 and keep his slim hopes of an upset alive.

Coming back in the set cost Khachanov too much though and the Russian was broken to love in the following game, losing eight points in a row as Djokovic ended the contest with an ace.