APOEL extended its surprising Champions League run with a 1-1 draw at Porto on Wednesday to stay unbeaten at the top of Group G.
Ailton's 19th-minute equalizer ensured five points for the Cypriot champion after three rounds, keeping it one point ahead of Porto and Zenit St. Petersburg in joint second.
APOEL previously upset Zenit and secured a draw at Shakhtar Donetsk, which is bottom of the group with two points.
Brazilian strikers got both goals at the Stadium of the Dragon to leave the group wide open.
Hulk put the home team ahead in the 13th with a left-footed free-kick that bounced in front of Dionisios Chiotis and crept inside to the post.
APOEL lived up to its billing as the group's surprise team, restricting Porto's attack with cool-headed defending and probing down the flanks to keep the home team's defense on edge.
Porto, a former European champion which won the Europa League last season, had most of the possession but couldn't make headway against its unheralded opponent.
''We didn't play very well, we were uneasy,'' Porto coach Vitor Pereira said. ''APOEL is a well-organized team with some fast players. They're not easy to play against ... they don't give you much space.''
Brazilian forward Kleber, returning from a three-week injury lay-off, twice tested the APOEL goalkeeper in the early stages. A loose ball from a corner bounced off the APOEL post in the 12th.
Constantinos Charalambides was a constant danger on the right wing while Ailton attacked through the middle.
Ailton won a free kick close to the Porto area in the 49th that Charalambides struck weakly.
APOEL goalkeeper Chiotis went off injured in the 51st and was replaced by Urko Pardo.
Nuno Morais, a Portuguese player at APOEL, won the ball in midfield and ran at Helton in the 62nd but hit the ball straight at the Porto goalkeeper.
Hulk tried his luck with long-range shots as APOEL blocked Porto's attempts to get closer and stifled the midfield.
Ailton almost got the winner in injury time but Helton sprinted out to close the striker down.
