London - Juan Del Potro almost threw away a 5-2 lead in the final set, with the US Open champion needing to top off victory with a winning tiebreaker to escape against Fernando Verdasco 6-4, 3-6, 7-6 (7-1) at the ATP World Tour Finals Tuesday. Roger Federer was poised to assure himself of the year-end world number one title through a victory later over Scot Andy Murray in the day's second Group B match at the season wrap-up.
US Open champion Del Potro came close to making a hash of a 5-2 lead in the final set against Spain's Verdasco.
The Argentine missed his chance to serve out the victory as he lost his serve in the ninth game of the concluding set, with Verdasco saving a match point, 4-5.
The Spaniard kept up the pressure to level at 5-all as another Del Potro match-winning opportunity slipped away.
It finally took a runaway tiebreak from a relieved Del Potro to seal his first win of the week after losing his opener to Murray.
Both players have made breakthroughs this season, with Del Potro winning his firstGrand Slam title at the US Open and Verdasco getting to the semi-finals at the AustralianOpen and subsequently cracking the Top 10.
Del Potro finished with ten aces and five breaks of serve.
The winner struck 28 unforced errors, ten less than his opponent who will join Rafael Nadal in next week's Davis Cup final in Barcelona against the Czech Republic.
Verdasco now stands winless in his debut at the year-end tournament after two matches.
