Cambridge United's financial director Richard Summerfield admitted in midweek they desperately needed to sell a player to survive and their victory over Orient might have identified prize prospects.
Goalkeeper Shaun Marshall, who spent two years in the shadow of French star Lionel Perez, pulled off a hat-trick of astonishing saves in the space of eight minutes in the first half.
Cambridge went on to win comfortably after the break but it would have been a very different match if their young keeper had not frustrated the London club when they had their spell of superiority.
Twice in five minutes Gary Fletcher and John Martin were through for one on ones but Marshall was able to deny them.
After those heroics in the 13th and 18th minutes he did it again in the 20th, grabbing the ball ahead of Lee Thorpe when the striker looked certain to head home at the far post.
Dave Kitson fired Cambridge in front after six minutes but they failed to follow up and a close match looked on when Orient eventually equalised in the 55th minute, a cross from Jamal Campbell-Ryce bouncing in off Luke Guttridge.
However, slackness at the corner allowed Phil Horner to restore Cambridge's lead and they then took complete charge as Orient faded.
Cambridge boss John Taylor said after the match: "Shaun pulled off some world class saves to keep us in it. But we grew and grew as the game went on and deserved the win in the end."
Orient boss Paul Brush blasted his team for squandering their chances.
He commented: "You should get something from the match. We had seven clear chances away from home. Their keeper was outstanding but we should have beaten him more than once.
"A lot of good football and plenty of bad, and nothing in between."