Six minutes after Porto forward Hulk had opened the scoring from a 20-yard free-kick, the visitors showed their mettle by scoring an equaliser and then proceeding to hold out for a valuable point.
It was not the kind of result the Portuguese side had in mind as they made a confident start, with Pinheiro Kleber bringing the first save out of visiting goalkeeper Dionissis Chiotis with less than eight minutes on the clock.
Chiotis saved again from the same player two minutes later before Hulk's low-driven opener, which came after the goalscorer had been fouled by APOEL's William Boaventura on the edge of the box.
Ailton rifled the equaliser in from 20 yards put with the visitors' first chance and the goal stung Porto, who failed to make their possession count, with Pinheiro firing wide and Chiotis saving well from Cristian Sapunaru.
The busy Chiotis parried a drive from Hulk on 24 minutes before APOEL came close to snatching the lead when Marcelo Oliveira met a Nuno Morais corner in front of goal but headed inches wide.
Chiotis saved again from Kleber and then from a wide free-kick by Hulk as the game approached half-time. And, a degree of frustration began to creep into the home side's play.
Chiotis was substituted five minutes into the second half and it didn't take his replacement Rafael Urko long to set about also frustrating Porto, saving well from Joao Moutinho.
Urko saved from Fernando Belluschi, but Porto were also guilty of missing chances themselves, with Hulk flashing a long-range free-kick wide then heading a fine cross from Silvestre Varela over the bar.
Varela missed Porto's final chance in injury time when he headed wide from six yards and there was still time for APOEL to seek a winner, Aldo Adorno's close-range effort well saved by Helton in the home goal.