ROTTERDAM - Juan Martin del Potro mowed down a surprisingly listless Tomas Berdych 6-3, 6-1 to reach the final of the Rotterdam Open on Saturday. The Argentine third seed needed just an hour and a quarter as he handed Berdych a first defeat indoors this season, following an eight-game winning run for the Czech that included this month's Montpellier trophy.Berdych barely registered in the match, which takes Del Potro into a final against either top seed Roger Federer or unseeded Russian Nikolay Davydenko. Federer leads Davydenko 16-2 in head-to-head encounters, losing his only two matches in the series in late 2009 and early 2010 before resuming his domination with wins in their last four meetings.Del Potro, who beat Federer for the 2009 US Open title before falling victim to the wrist injury that kept him out for a year, never let Berdych into the one-way match. "I played almost perfect," said Del Potro, who has lost just five games in his last two matches."I was focused all the time on trying to break and on hitting my forehand. I've been improving match by match, but I need to play better in the final if I'm going to win this tournament. That has been the goal this week." Del Potro picked up where he left off against Berdych, whom he beat in two previous matches in 2009 before his wrist injury problem surfaced.The Argentine began the afternoon at the Ahoy stadium with a break and never hesitated to carry his momentum forward against Berdych, who finished with a disappointing win-loss ratio of 1-8 in semi-finals in 2011. Del Potro ran off seven straight games from mid-way in the opening set to the sixth game of the second, when an off-colour Berdych finally got one.But it was immediately back to business for Del Potro, who won the last two games and signed off with a ninth ace of the match on his first match point. "Berdych is tough, with a big serve," said Del Potro. "I had to stay in control against him. His game is aggressive like mine, but I played better than him today."