Four days is clearly a long time in football. On Saturday, Tottenham produced a weak display, with only one attempt on target as they fell to a tame loss to Chelsea, with pressure mounting on Thomas Frank.
But this reaction was exactly what both Spurs and Frank needed, with a jubilant home support clearly loving what they were seeing.
When the home side went down to 10 men just after the hour-mark, most in the ground would have got nervous and expected a Copenhagen fightback.
Frank took off the superb Xavi Simons to strengthen the midfield by bringing on Joao Palhinha and it became a lesson in how to play with a man disadvantage, countering with pace and looking a threat every time they progressed.
In the end, the winning margin could have been wider with Richarlison, who had earlier hit the post, firing his 93rd-minute penalty against the underside of the crossbar.
Spurs opened the scoring in the 19th minute, pouncing on Gabriel Pereira's loose pass, which was collected by Rodrigo Bentancur and moved on to the excellent Simons.
He played a clever pass over the visiting defence and Brennan Johnson, who scored the only goal when Spurs beat Manchester United in the Europa League final to qualify for this tournament, kept his composure to go around the advancing goalkeeper Dominik Kotarski before calmly finishing.
Wilson Odobert added a second after Randal Kolo Muani had charged down a clearance from Kotarski, before Johnson's dismissal.
But the tension was lifted by Micky van de Ven's incredible individual effort, with Palhinha adding a fourth.
Tottenham fans had been unhappy with their home form, which had seen them only pick up one point from their past three Premier League games, but this was a perfect way to get the supporters back on side.
Credit also must go to the Copenhagen fans, who created a superb atmosphere as they did not stop chanting, singing and bouncing, even though their team were handed a thrashing by a rampant Spurs outfit.