Manchester United revisited their Champions League handbook on how to make Thorsten Fink suffer. In 1999 he was the Bayern Munich substitute introduced to tighten a midfield on the cusp of final glory in Barcelona. We know how that ended. Here, in the guise of Basel coach, he was seconds from completing an astonishing comeback of his own. He should have known, that with United, another "football, bloody hell" moment is never far away.

With seconds remaining and Old Trafford braced for its first European home defeat since November 2009, Fink withdrew a striker for a midfielder and prepared to celebrate a result to undermine claims of sterility and unpredictability in the group stages of the Champions League. United had squandered a two-goal half-time lead through a combination of laboured defending, complacency and Basel finishing that was transformed after the break. An alarming loss beckoned, then Nani swung over an exquisite cross and Ashley Young appeared unmarked at the back post to head home a 90th-minute equaliser. There was no Samuel Kuffour figure pounding the turf in despair this time, only a Basel team accepting the acclaim from their supporters up in the gods. But it should have been much more.

"There was a carelessness about us throughout the game," Sir Alex Ferguson said. "We played too many players forward, far too many, and though we prepared properly there is a possibility that playing a team like Basel, the players think they can do that. We left too many spaces between our midfield and back four. If we had concentrated on the defensive part we might not have had as many problems. Complacency may have been a part."

Until Fink reminded his players at half-time that Basel had crafted three glorious chances despite United's first-half ascendancy, and should dispense with their nervousness, this had seemed a procession for last season's runners-up and vindication of Ferguson's decision to start Danny Welbeck ahead of Dimitar Berbatov. Only the latter remained true by close of play.

Welbeck, watched by the England general manager, Franco Baldini, and a strong candidate to start against Montenegro next Friday should Wayne Rooney fail to recover from injury, scored the first two Champions League goals of his career to take his tally for the season to four in seven appearances. His sharpness inevitably faded as the game progressed following a recent hamstring strain. There was less excuse for United's ponderous defending, with Rio Ferdinand and Patrice Evra enduring nights to forget.

Ferguson said: "It's possible [defensive disruption had cost United] but there is still enough quality in the back players. Ferdinand and Evra are both very experienced. You always like to have a back four playing consistently together but we've not got that at the moment. The quality in our forward positions guarantees us goals and we really should have put the game to bed in the first half."

Hindsight suggests United's players thought they had done exactly that. Basel were hapless in defence and up front and the home side had created three clear opportunities before Welbeck delivered following a commanding run out of defence by Phil Jones. Antonio Valencia and Fábio da Silva combined before Ryan Giggs set up the 20-year-old for a scuffed finish into the bottom corner.

Within a minute Welbeck had doubled United's lead and his personal European account to start an inquest among the Basel defence. Giggs collected Michael Carrick's crossfield pass and arrowed a low cross through the penalty area that Aleksandar Dragovic inexplicably allowed to run across him. United's forward, lurking behind, converted the gift and the ninth assist Giggs has provided in his team's last 13 Champions League goals.

The home defence was creaking long before Basel's recovery gained substance. Alexander Frei wasted two free efforts before the break, Jacques Zoua sliced into the side-netting from four yards out and David de Gea's foot intervened when Evra followed the play inside and allowed the impressive Marco Streller a clear sight of goal. The night of living dangerously then cost United dearly as Streller beat Ferdinand to a Basel corner and, though De Gea saved his glancing header, Fabian Frei swept in the rebound via a post.

Basel's equaliser followed swiftly as they exposed United's frailties at the back. With Jones and Evra lulled out of position, Fabian Frei exploited space on the visitors' right and delivered a textbook cross on to the head of Alexander Frei. Seconds earlier Ferdinand had escaped with a blatant foul on the Basel forward on the edge of his area. Revenge was served instantly as Frei found the top corner.

Basel were not finished there. Jones played Valencia into trouble with a dangerous clearance to the edge of his own penalty area. Streller dispossessed the converted full-back who tripped him inside the area and gave the Italian referee no hesitation in pointing to the spot, and Alexander Frei the chance to send De Gea the wrong way from 12 yards. "It was never a penalty kick," Ferguson said. "It was a poor decision I felt."

The spirit that has saved United so often in Europe, as Fink knows only too well, came to the fore as Young equalised, Welbeck just failed to get his forehead on the chance for a hat-trick, Berbatov missed and De Gea almost allowed a defensive punt to sail under his guard in stoppage time.