Lloyd James fired a 42nd-minute penalty as Leyton Orient secured a 1-0 half-time lead over Swindon Town at the Matchroom Stadium this afternoon.
Orient's forward David Mooney and Chris Dagnall combined to fashion the game's first chance, with the latter crashing his effort off the post following a well-weighted cross from his strike partner.
Dagnall menaced once more in the final five minutes of the half to set up Moses Odubajo, but the winger thrashed wide of the mark from a good position.
Odubajo made amends for the miss shortly before the break by drawing a foul from Jake Bidwell in the area, before James stepped up and slotted beyond Button from 12 yards to give the hosts a slender lead at the break.