Chris Taylor also makes Oldham Athletic debut following Deadline Day move
Jamie Proctor scored the winner on his Carlisle United debut before being sent off after joining the Cumbrians on loan on Deadline Day.
Starting in attack away at Leyton Orient, the forward headed Carlisle into a 2-1 lead midway through the second half having seen Gavin Massey and Gary Liddle exchange strikes in the first half.
However, Proctor's joy turned to misery minutes later as he was dismissed after picking up two bookings in quick succession.
But despite finishing the game with ten men, his new team-mates held on to clinch the three points.
Elsewhere, Chris Taylor made his second debut for Oldham Athletic after rejoining the club on loan.
The midfielder completed 78 minutes for the Latics as they won 1-0 away at Chesterfield despite seeing Anthony Gerrard sent off on the stroke of half-time.
Peter Clarke scored a last-minute winner for Oldham, to ensure both Wanderers loanees enjoyed winning starts at their new temporary homes.