They pulled on a minty green kit and Ange Postecoglou threw in some fresh faces but Tottenham found it tough to shake off the stale odour that has been following them around.
Just four days after a home defeat in the North London derby on a day when Postecoglou reminded the world how he never failed to win a trophy in his second season, Spurs required a late salvage operation to avoid defeat in the Carabao Cup.
Coventry led deservedly with 88 minutes played but Djed Spence equalised and Brennan Johnson dashed clear to win the tie in the second minute of stoppage time as penalties loomed.
It was heartbreak for the Championship team who had been the better team for large parts of the tie, and might have been ahead before Brandon Thomas-Asante struck in the 63rd minute.
Having started with a team which cost almost £250million, Spurs had just sent on Heung-min Son and James Maddison when Thomas-Asante put them behind.
Postecoglou then threw on Dejan Kulusevski, Tottenhem refused to give up and Coventry finally faded under the pressure.
Djed Spence replaced Udogie and Spurs returned to find a better tempo at the start the second half, which served to tear the game wide open, with Coventry looking increasingly dangerous on the break.
Forster saved again from Bassette and then charged out of his penalty area and felled Bidwell. The ball spilled to Haji Wright who was unable to find the net. Davies slid across to block. The surprise was that referee Darren England did not go back to punish the goalkeeper for a foul but gave a corner. Home fans were hopping mad
Ben Wilson made a fine save to deny Davies from a corner but Coventry took the lead through Asante-Thomas sweeping in a low cross by Bassette after a dashing move down the left wing.