Sheffield United set a new club record of 12 away league games unbeaten with victory over Coventry.
Blackwell's side set club record on the road
Sheffield United set a new club record of 12 away league games unbeaten with victory over Coventry.
But more importantly for Kevin Blackwell's side, the three points kept their Championship play-off challenge firmly on track and moved them up to fourth in the table - six points away from an automatic promotion spot.
The Blades took the lead in controversial circumstances in first-half injury-time through Leigh Bromby.
Television replays showed that the defender's effort did not cross the line but there was no argument in the 54th minute when captain Chris Morgan powered home a header to double his side's advantage.
City skipper Scott Dann replied with a headed goal midway through the second half to set up a tense finale but United held on.
Keiren Westwood was the first keeper to be called into action. Morgan managed to nod the ball goalwards, but Westwood athletically tipped the defender's effort over the crossbar.
From the resulting corner, the ball found its way to Darius Henderson at the far post but he blazed his shot into the stand.
Cotterill flashed a shot just wide from 25 yards after cutting infield from the left-hand side before the Blades opened the scoring.
Recovered
Stephen Quinn beat Westwood to the ball on the byline and, with the keeper stranded, crossed to the back post.
Henderson looked certain to score but Westwood somehow recovered to palm away his header on the line.
The ball landed perfectly in Bromby's path six yards out and he volleyed goalwards but Westwood again scrambled across his line to make the save.
However, the referee's assistant on the far side ruled that the ball had crossed the line with Westwood vehemently claiming he had kept out Bromby's effort.
He chased referee Kevin Wright back to almost the halfway line to contest the decision and was booked by the Cambridgeshire official for his protests but video replays justified the City keeper's actions.
Morgan timed his run perfectly to head home unmarked at the far post from Brian Howard's free-kick on the left-hand side.
Jordan Henderson steered an effort just over from the edge of the area but it would not be long before Coventry were back in the game.
Chris Coleman's team had played some superb free-flowing football, but the goal to half their deficit after 70 minutes was as route-one as they come.
A long throw by Aron Gunnarsson was nodded into the bottom corner by Dann from six yards out.
The Sky Blues piled on the pressure in the closing stages but were unable to find their way past a resolute United defence.
