Japanese tennis player Nishikori Kei has been defeated in the first round of the Australian Open.

Nishikori, ranked 42 in the world, lost to 16th ranked Pablo Carreno Busta of Spain in straight sets on Monday.

In the first set, both players broke each other's service games. Nishikori was forced back by his opponent's powerful strokes, and lost the set 5-7. Nishikori lost the second set 6-7 after a tiebreaker and was overwhelmed 2-6 by his opponent in the third set.

This is the first time Nishikori has been defeated in the first round of the Australian Open since he made his tournament debut in 2009.

Nishikori was placed under a strict two-week quarantine without practice outdoors along with other players, after it was discovered their flights to Australia had people who tested positive for the coronavirus on board.