ROTTERDAM  - Juan Martin delPotro spent just over an hour in reaching the second round of the Rotterdam World Tennis tournament as he dispatched France's Gael Monfils 6-3, 6-4 on Tuesday.The second seeded Argentinian is keen to improve on last year's loss in the final to Roger Federer in what was his first appearance at the tournament. Del Potro broke Monfils for 5-4 in the second set and sealed victory a game later as he beat a player who spent much of last season injured. "He's dangerous coming back from injury and is playing well," said the 24-year-old South American."I'm glad to be back in Rotterdam, though my memories are not the best on court after losing a year ago to Roger." Monfils said that he missed his chances in what he knew would be a tough match no matter whom he played. "I'm unseeded, so I can get anyone in the first round. It took me three games to get used to the court and the ambience. I then started seeing the ball better," said the 26-year-old injury-prone Frenchman."In the second set I played two bad service games. He's not in the top 10 for nothing so he took advantage, It was a matter of me not taking the opportunities that I did have. "I'm disappointed to lose but know that I can work harder and improve. My legs and hamstrings feel good and my mind is clear. I'm happy to be back competing."Earlier Monfils' compatriot JulienBenneteau joined another Frenchman Gilles Simon in the second round as he beat lucky loser Tobias Kamke of Germany 6-3, 6-2. Their progress - Simeon eased through on Monday - offset the disappointment of French number one Jo-Wilfried Tsonga going out on Monday to unheralded Dutchman Rigor Sibling in three sets.The victory over Kamke, who was drafted into the tournament proper when another Frenchman Michael Llodra pulled out through illness, sets Benneteau up with a second-round match against Romanian Victor Hanescu. Dutch players enjoyed mixed fortunes, with Thiemo de Bakker advancing as Russian opponent Mikhail Youzhny was forced to retire in the third set with a hip problem.De Bakker will await the winner from Wednesday's match between top seed and holder Roger Federer and GregaZemlja of Slovenia. Latvian qualifier ErnestsGulbis admitted he had little to lose in his comprehensive defeat of Dutchman Robin Haase 6-2, 6-1, which took just 50 minutes with the winner breaking four times. Gulbis, who reached a career-high ranking of 21st two years ago, now stands 132 and finished out of the ranking top 100 last season for the first time since 2006."I'm sorry Holland for beating a local," joked the Latvian. "I played well and had almost perfect timing. I really didn't give him any chances. "I don't have many expectations, my ranking is so low I barely got into qualifying anyway."