Premier League leaders Chelsea endured an almighty struggle against fourth-tier Shrewsbury Town before eventually booking their place in the Capital One Cup quarterfinals thanks to Jermaine Grandison’s late own goal. The defender turned the ball into his own net with only nine minutes remaining and only four minutes after Andrew Mangan cancelled out Didier Drogba’s opener early in the second half. An improbable extra 30 minutes and possibly penalties had looked on the cards and arguably would have been a deserved reward for a superb performance at Greenhous Meadow by a side sitting 72 places behind their illustrious visitors in the league pyramid. Chelsea survived, but only just.

Just over 48 hours after Drogba’s header was cancelled out in injury time by Robin van Persie at Old Trafford, Chelsea manager Jose Mourinho unsurprisingly made a number of changes to his starting lineup. There was a debut for defender Andreas Christensen at right-back, alongside 20-year-old Kurt Zouma and 19-year-old Nathan Ake.

The seven changes in total made for a disjointed performance for the visitors in the first half, as Micky Mellon’s side more than held their own. Shrewsbury had the clearest opening of the opening period, too, when Nathaniel Knight-Percival rose highest at the back post from a corner and his downward header required Petr Cech to be alert just five minutes into only his third start of the season and claw off the line.

At the other end there were occasional flashes from Mohamed Salah and Andre Schurrle, but from both an end product as sorely missing. Seeking to progress in a competition that supplied his first trophy in England 10 seasons ago, Mourinho will surely have had some stern words at the interval. Certainly there was extra vigor in Chelsea’s play early on in the second half.

Shrewsbury were appearing overwhelmed for the first time and, having just seen a shot from Oscar deflected wide, the League Two outfit succumbed. Schurrle was the architect, cutting at pace from the right, before his pass deflected into the path of Salah who shrewdly laid it square for Drogba to meet with a clinical low strike into the net. Even with Diego Costa and Loic Remy ruled out through injury, there was some surprise that the veteran Ivorian was starting for the second time in such quick succession. But he once again vindicated Mourinho’s decision to bring the Stamford Bridge legend back to the club in the summer.

Having gotten the breakthrough, the odds favored Chelsea going on to secure a more comfortable passage to the last eight. But after Schurrle had seen a fine drive from distance tipped over by Jayson Leutwiler, Shrewsbury found fresh impetus. The lively Jean-Louis Akpa Akpro saw a goal-bound strike deflect wide off teammate James Collins after a free-kick, and minutes later Chelsea were punished for again failing to effectively deal with a set-piece. This time from a corner, Grandison’s header struck John Mikel Obi, who couldn’t adjust fast enough to clear, allowing Mangan to turn and fire past Cech to the delight of a record crowd of over 10,000 in attendance.

Perhaps Shrewsbury’s inexperience at this elevated level showed, though, as their fine efforts were soon undone. Willian made an almost instant impact after being sent on with a cross that was aimed toward Drogba but that Grandison, under pressure from the Ivorian, turned past his own goalkeeper.