The East London side provided a tough test for the First Division promotion hopefuls and their were plenty of chances for both teams before the midfielder opened the scoring after 25 minutes when he slotted home from 10 yards. Leyton Orient equalised shortly afterwards when form Lions-target Matt Lockwood was the first to react after his penalty was saved by Tony Warner.
Cahill sealed the win eight minutes after the restart when he powered home a header from a Steven Reid corner. Defender Mark Phillips was denied a third by the woodwork but it was Warner who proved to be the busier keeper in the closing stages, making two fine saves to prevent an equaliser for the O's.