SHANGHAI, Nov 11: World number three Novak Djokovic survived a big scare against Nikolay Davydenko to reach the Masters Cup semi-finals on Tuesday.

A day after four-time champion Roger Federer slumped to Gilles Simon, the Australian Open champion won the first set but fell apart in the second before rallying to win 7-6 (7-3), 0-6, 7-5.

The result means Djokovic tops Gold Group and eliminates Jo-Wilfried Tsonga, who was beaten by Juan Martin del Potro earlier.

Djokovic recovered from an early break to dominate the first-set tie-break, setting up three match points with a pair of screaming aces and taking the lead when Davydenko double-faulted.

A convincing win looked on the cards but Djokovic followed Federer by imploding in the second set, ranting and hurling his racquet as he dished up a series of unforced errors including a wide forehand to level the match.

But Djokovic survived early break points in the third and his composure grew as he walloped a forehand and Davydenko misfired for the crucial break 6-5. Another big forehand was enough to seal the match.

Djokovic lost all three group matches on debut last year, while Davydenko has qualified for the season finale four times and reached the semi-finals in 2005.

The two had never completed a match together after the Serb withdrew from their Davis Cup meeting in February complaining of dizziness and exhaustion.

Earlier, del Potro won a tense encounter with French livewire Tsonga 7-6 (7-4), 7-6 (7-5) to breathe life into his campaign after his opening loss to Djokovic.

The 20-year-old Argentine showed steely determination as he won two gripping tie-breaks to revive his semi-final hopes.

Tsonga, who won this month’s Paris Masters, is out after losing both his opening matches.

Results (round-robin):

Gold group: 7-Juan Martin Del Potro (Argentina) bt 6-Jo-Wilfried Tsonga (France) 7-6 (7-4), 7-6 (7-5); 2-Novak Djokovic (Serbia) bt 4-Nikolay Davydenko (Russia) 7-6 (7-3), 0-6, 7-5.—AFP