Copenhagen held Porto to a 0-0 draw in the Champions League to keep the race for second place in Group G alive.
After this scrappy stalemate at Parken Stadium, the Danish side remain two points behind their visitors with one game to play as both look to join group winners Leicester City in the last 16.
Having drawn 1-1 in Portugal earlier in the campaign, the two teams were again finely matched in a game that lacked quality as opportunities came at a premium.
The chances that did arrive were squandered, with Copenhagen goalkeeper Robin Olsen's double-save keeping out Andre Silva when the Porto man really should have opened the scoring in the second half.
Erik Johansson had earlier headed the home side's best opening wide, and their attacking threat waned in the absence of top-scorers Andreas Cornelius and Federico Santander.
Copenhagen now require a favour from Leicester as they travel to Porto on matchday six, but Stale Solbakken's men must also show more against Club Brugge in order to keep their last-16 hopes alive.
Without their influential forward men, the hosts made a slow start while Porto failed to profit from a number of dangerous crosses into the area.
Copenhagen grew into the first half, though, and Iker Casillas was required to make a smart stop from Peter Ankersen's low 20-yard drive.
Oliver Torres' fine work on the left for the visitors then set Silva away, but the Portugal international cut inside and sliced a horrible shot away towards the corner flag.
Again the Danes responded, with Youssef Toutouh's cross, at the end of a magical run, nodded past the post by Johansson.
Olsen was finally called into action for the first time after the interval, showing off his reflexes to twice deny Silva after Mathias Jorgensen had hesitated in front of his own goal.
The Copenhagen keeper was then tested further as he gathered Diogo Jota's thumping shot and turned a tame Danilo Pereira volley away from his bottom corner.
With Solbakken's men now hanging on, Silva lashed high and wide, and Jota did likewise after a speedy break.
Neither side could find a breakthrough in the closing stages, though, leaving the group still finely poised.