Those seeking omens could point to the fact that a year ago today Liverpool lost at home by an identical scoreline to Austrians Graz en route to eventual success in the competition, but there could be no disguising that this was hardly a morale-boosting way to enter tomorrow's draw for the group stages.
A mere 90 days removed from that unforgettable night in Istanbul, Liverpool embarked upon their sixth preliminary tie in defence of their crown against a relaxed Bulgarian side, manager Rafael Benitez electing to rest five of his first-leg starters in light of the 3-1 cushion.
Such optimism looked well placed in the opening minutes as the champions took the game to Sofia, but decidedly less so after a quarter of an hour. By that stage, the Bulgarians led on the night, the product of a a superbly struck goal from Valentin Iliev. Momo Sissoko conceded a foul on Sofia captain Emil Gargarov to the right of the Liverpool area and Yordan Yurukov's free-kick found Iliev, inexplicably unmarked just inside the area. The defender curled a shot beyond Scott Carson's dive into the corner of the net.
A healthily sized crowd were stunned but found their voices, in disapproval, five minutes later when CSKA came close to doubling their lead. Dah Zadi broke through the Liverpool defence, only to be denied by Carson's legs just outside the area, leaving Yordan Todorov with time to size up the target which he missed from 25 yards.
There had been no hint of the minor collapse to come as Liverpool took the game to their hosts in the early stages, Djibril Cisse forcing Dejan Maksic into an early, sprawling save as he chased on to a through ball from John Arne Riise. Cisse and Fernando Morientes then exchanged passes but Cisse's insistence on standing acres offside left the latter with no option but to send a shot over the bar.
It was a mental lapse for which Cisse almost made amends as Liverpool sought the equaliser, the striker gathering Dietmar Hamann's short, 25th-minute free kick and delivering a vicious long-distance shot that was well smothered by Maksic.
But any notion that CSKA had exhausted their attacking potential for the evening proved misplaced, the Bulgarians' passing becoming more confident and adventurous as the half progressed. There were a number of promising counterattacks, one in particular requiring the urgent intervention of Sami Hyypia to keep Yurukov's cross away from two visitors lurking at the far post.
By the time Sissoko had driven a low shot harmlessly wide and Riise's free-kick had risen high over the target, Benitez had seen enough and the interval brought change, Luis Garcia coming on for young midfielder Darren Potter in a straight swap out on Liverpool's right wing.
Within seconds of the restart, Riise almost had Liverpool level, three times. First, his long, swirling shot was tipped over by the vigilant Maksic then the Norwegian midfielder collected a Morientes pass and deposited an effort into Sofia's side-netting. Soon, Riise made it a hat-trick of chances when Steve Finnan's right-wing cross was headed down by Iliev and Riise shot well over.
Not that the Bulgarians were out of contention. With 35 minutes left, Mourad Hdiouad received Yurukov's short free-kick 20 yards from goal and beat the wall with a shot that flew inches beyond the left-hand post.
Riise, from a free-kick, yet again came close as did Garcia, shooting into the keeper's arms, and Morientes, denied by Hdiouad's goal-line clearance.