 His first three years at the Gelsenkirchen side were successful individually – 22 goals combined – and the 1996–97 season brought with it the UEFA Cup conquest, with the player netting three times in the campaign, including once in the quarter-finals against Valencia CF.Additionally, Mulder also won two consecutive German Cups, in 2001 and 2002.Only managing to appear 33 times (with just one goal) in his last three seasons combined, he retired at the end of 2001–02, aged 33.