He replaced the injured Sean Long for Saints in their opening play-off game against Leeds three years ago, nervelessly kicking three goals in a tense 10-8 victory.
Long nervelessly converted a fifth-minute penalty he had won himself and might have claimed a second goal just after the restart as he proved an able deputy to injured skipper Robbie Keane.
In fact, the striker had to do it twice after referee Mike Ryan ruled out his original kick for encroachment, Iwelumo nervelessly slotting into the same bottom left-hand corner of Stewart's net on both occasions.
The Swede had a first ever win over Federer in his sights and he served out nervelessly to set up a semi-final against Tomas Berdych, who thrashed Mikhail Youzhny 6-3 6-1 6-2 on Court Suzanne Lenglen.