Novak Djokovic faces a nervous wait to discover if his season has come to a disappointing end at the ATP World Tour Finals after the world number one lost 3-6, 6-3, 6-3 to Janko Tipsarevic on Friday.
Djokovic has lost two of his three Group A matches in the season finale at London’s O2 Arena, but he will still qualify for the semi-finals if David Ferrer beats Tomas Berdych in Friday’s late match, while a Berdych victory would eliminate the Serb.
After a magnificent season that brought Djokovic three Grand Slam titles, five Masters crowns and top spot in the world rankings, the 24-year-old has finally run out of steam this week.
He arrived in London on an incredible run of 69 wins from 73 matches, but that record has been slightly tarnished by two successive defeats here.
Djokovic’s lacklustre loss against Ferrer on Wednesday had taken his tournament fate out of his hands and his season could be over after he allowed a one-set lead to disappear against fellow Serb Tipsarevic.
“There were a lot of ups and down from both Novak and me, but I am very happy to be here after starting this year at 49 in the world,” Tipsarevic said.
“I generally do not like to play my fellow countrymen, but even during the match I felt proud just to see the two Serbia flags in the O2 Arena.”
It could have been so different after a bright start from Djokovic earned him a break in the fourth game of the first set.
Tipsarevic, called into the tournament as a replacement for the injured Andy Murray, knows Djokovic’s game better than most after spending hundreds of hours on the practice court with his compatriot.
But the world number nine, already out of contention for the semi-finals after losing to Berdych, still could not find a way to stop Djokovic cruising through the rest of the set.
The tournament’s complicated qualification criteria meant a straight sets victory would improve Djokovic’s chances of advancing.
However, Djokovic admitted after the Ferrer defeat that he was not operating at 100 per cent after such a long season and his stamina reserves reached breaking point as Tipsarevic won a 12-minute game to open the second set.
Tipsarevic took advantage of Djokovic’s slump with a break for a 4-2 lead when the world number one rashly attempted a drop-shot that flopped into the net.
Djokovic replied with a break of his own, but Tipsarevic was growing in confidence as his compatriot’s energy drained away and he broke again to clinch the set.
There was a noticeable lack of bite to Djokovic’s ground-strokes now and he was seemingly content just to keep the ball in court rather than go for winners.
Tipsarevic made him pay in the opening game of the final set with a sublime angled volley to secure the decisive break.
Djokovic, clearly running on fumes, never threatened to mount a comeback and Tipsarevic put him out of his misery with another break to wrap up his first ever win over his old friend.