And he haunted the same side again, taking David Healy's pass in his stride before expertly clipping the ball past keeper Stephen Bywater from 8-yards.
Former Yeovil and Hereford winger Gavin Williams thought he had rescued a point for the promotion-chasing Hammers with a 68th minute equaliser after Rob Hulse had volleyed Leeds into a 51st minute lead.
Alan Pardew made two changes from the side that won 1-0 at Gillingham, Teddy Sheringham returning to replace Bobby Zamora in attack and Williams coming in to give the Hammers more width on the right hand side, with Nigel Reo-Coker dropping to the bench.
Williams, who also hit the Leeds post on 55 minutes, fully justified Pardew's decision to restore him to the side in place of Reo-Coker.Leeds recalled former Hammer Matthew Kilgallon in place of Clarke Carlisle while Simon Walton came in for Jermaine Wright.
Leeds had a penalty shout rejected when Gary Kelly's 29th minute corner struck Anton Ferdinand on the arm.Ferdinand often showed the composure normally associated with his elder brother, Rio, but the central defender limped off just before the interval, Hayden Mullins leaving the bench.
Leeds certainly enjoyed the better of the attacking pressure in the first-half, but Bywater or indeed Neil Sullivan had hardly been threatened as the teams left the field still deadlocked at 0-0.
Leeds' supremacy eventually paid off when Aaron Lennon cut in from the right and crossed for Hulse to volley powerfully past Bywater from 6-yards with the defence asleep.But the Hammers first shot on target brought an equaliser. Steve Lomas lofted the ball forward to Sheringham who chested it down and Williams' deflected shot from 18-yards looped over Neil Sullivan into the net.
With 73 minutes gone, possibly the most crucial moment in the game, when Williams jinked his way into the Leeds penalty area only to be stopped by a great tackle from Walton. A second goal for the Londoners then and Leeds would have been out of it.
Matthew Etherington's free-kick then hit a post and the Hammers luck was out again when Derry skipped through for the late winner.