Defending champion Rafael Nadal has been knocked out of the Australian Open in the second round after suffering an injury during his 6-4 6-4 7-5 defeat by American Mackenzie McDonald.

Nadal’s elimination on Wednesday shakes up the men’s draw and puts a twist in the Grand Slam titles race,

with nine-time champion Novak Djokovic able to draw level with the Spaniard’s 22 major championships should he take a 10th crown at Melbourne Park.

Nadal appeared to suffer a strain in his left hip area while running for a backhand deep in the second set at Rod Laver Arena

and after receiving attention from a trainer he took an off-court medical time-out when trailing 6-4 5-3.

He returned, grim-faced, to play out the match but his movement was clearly affected, particularly on his backhand side,

Before the injury, McDonald had played superbly to take the first set, going toe-to-toe with the 36-year-old Spaniard and winning most of the ferocious baseline exchanges.