Paul-Henri Mathieu fought back from a set down Monday to upset fourth-seeded Feliciano Lopez 4-6 7-6 (7-5) 6-4 in the opening round of the ABN Amro World Tennis Tournament.

Sixth-seeded Alexandr Dolgopolov of Ukraine also went out in the first round, losing 6-7 (7-4) 6-4 6-2 to Lukasz Kubot of Poland.

Mathieu, ranked 733 in the world after missing the entire 2011 season with a knee injury, looked sharp in beating Lopez in a match that lasted nearly three hours.

“I worked hard during my injury and I think I am fit,” he said. “This is a good comeback.”

Another Frenchman, fifth-seeded Richard Gasquet, overcame an injured Flavio Cipolla to win his first-round match 6-3 1-6 6-1.

After losing the first set, Cipolla easily took the second, but struggled in the decider with a left thigh injury.

Jesse Huta Halung advanced to the second round at the expense of two-time Rotterdam finalist Ivan Ljubicic. The Dutchman won 7-6 (8-6) 6-3 against the 2005 and 2007 runner-up to secure his first ever win at the tournament.

He next meets the winner of Thiemo de Bakker’s match against seventh-seeded Viktor Troicki.

Another Dutchman, Robin Haase, faces Nikolay Davydenko Tuesday with fellow Russians Mikhail Youzhny and Igor Kunitsyn also meeting later in the day.