US Open Champion Juan Martin Del Potro had to dig deep before seeing off Fernando Verdasco to keep alive his hopes of qualifying for the Semi Finals of the ATP World Tour finals in at the O2 Arena in London.

Del Potro stunned the tennis world when he beat Roger Federer to win the US Open in September.

Del Potro got the early break against Verdaso and held on to win the opening set 6-4 and at this stage the Argentine appeared to be in control of proceedings.

Verdasco to his credit broke Del Potro back in the 8th game of the 2nd set and went on to seal the 2nd set 6-3 to levle the match at one set all.

Del Potro then had a match point at 5-2 in the final set but Verdasco fought back in incredible fashion and took the decider to a tiebreaker but Del Potro ultimately proved too strong as he won it by 7 points to 1.

If Del Potro can maintain this form then he has every chance of upsetting the Betting Odds and winning the title on Sunday.