And what a difference four days make. The weekend protests calling for the sacking of manager Steve Kean seem even more distant now after Rovers won back-to-back matches for the first time since January 8.
Saturday's 4-3 victory over Arsenal brought renewed confidence to the squad after an awful start to the campaign but it remained fragile and a slip-up against lower-league opposition on Tuesday night would have put them back to square one.
But after a number of half-chances went begging in the first half 33-year-old Jason Roberts, in his sixth season at Ewood Park, eased the nerves with a penalty just before the interval.
After the break two recent arrivals, January signing Ruben Rochina and Simon Vukcevic, who joined last month, scored goals at important times after David Mooney had briefly equalised.
Dean Cox's late consolation was almost expected such is the way Kean's season has gone so far but it was not enough to halt Rovers' revival.
It was virtually all one-way traffic in the first half as, even taking into account a gap of 52 league places, Orient played like a side who won just once - in the last round - this campaign.
Rochina began the match in a nominal left-sided midfield role but he was afforded the freedom of Ewood Park by the visitors as he roamed throughout the final third.
The midfielder, signed from Barcelona in January, provided Rovers' creative focal point but what they lacked was a cutting edge with Saturday's two-goal hero Ayegbeni Yakubu dropped to the bench alongside fellow centre-forward Mauro Formica and lightning-quick forward Junior Hoilett.
Into their place came Roberts and reserve-team striker Nick Blackman, making his first start on only his second first-team appearance.
Despite his inexperience the 21-year-old looked confident and after coming close to connecting with Rochina's left-wing cross to the near post he drilled a long-range shot just wide.
Roberts, who has made more appearances in a BBC studio for radio phone-ins than he has for Rovers this season, had one darting run inside the area which was crowded out by Ben Chorley and goalkeeper Lee Butcher.
Rochina continued to prompt and probe but while he created the openings his team-mates continued to pass them up.
Having released Blackman down the right with a perfectly-weighted through-ball he could only watch as Vukcevic, the summer signing making his first start, drilled the low cross into the side-netting.
If Terrell Forbes was fortunate to escape conceding a penalty when he appeared to pull down Roberts by his shirt as he tried to control Vukcevic's cross, then Elliot Omozusi was less so.
The 22-year-old right-back was caught out by Martin Olsson's pace as he burst into the area and he clipped the defender to provide Roberts with his first goal of the season.
Orient were made to wait for their hosts to reappear for the second half but whether it was that which spurred them into life or manager Russell Slade's words at the interval, they came out more positively.
Jimmy Smith's looping header from Cox's corner dropped on top of the net before Mooney then displayed the sort of deft touch worthy of the Premier League when he killed Butcher's long free-kick in an instant before unleashing a low shot which Bunn saved at the near post.
It appeared Mooney's finishing was not quite top-flight standard as with only the goalkeeper to beat he shot straight at Bunn after a quick counter-attack left the Rovers defence exposed from George Porter's pass.
However, the 26-year-old made amends in the 64th minute with a smart finish from Porter's cross which warranted a better audience than the paltry crowd inside Ewood Park.
But Rovers bounced back six minutes later when Roberts' shot was half-saved by Butcher and Rochina rolled the ball into an empty net for his fourth goal in as many matches.
Hoilett was denied by Butcher for a second time since coming on at half-time but the goalkeeper could not keep out Vukcevic's powerful 75th-minute shot after Ryan Lowe's cross was only half-cleared.
But there was no straightforward end for Rovers as Cox's shot went in off the post with three minutes remaining, although it came too late to force extra-time.