* Atletico denied by 74th-minute own goal
* Draw boosts Zenit qualification hopes (Adds quotes)
ST PETERSBURG, Russia, Nov 26 (Reuters) - A goalkeeping blunder by Atletico Madrid's Thibaut Courtois gave Zenit St Petersburg a qualification lifeline as they fought back to draw 1-1 in their Champions League Group G match on Tuesday.
Toby Alderweireld deflected a right-wing Igor Smolnikov cross towards the net in the 74th minute and Belgian Courtois, on loan from Chelsea, flapped at the ball as it dropped over his head into the net for a precious equaliser for the Russians.
Zenit are second in the table with six points from five matches, two more than Porto ahead of the Portuguese team's tussle with bottom club Austria Vienna later on Tuesday.
Leaders Atletico (13 points), already through to the knockout stage as group winners and missing several regulars, went ahead in the 53rd minute when Adrian Lopez raced clear on the left before slipping the ball under keeper Yuri Lodygin.
"Both sides played well and in an organised way," said Zenit's Italian coach Luciano Spalletti. "Atletico sat back while we attacked because we needed to get a result.
"They tried to attack on the break when the opportunities arose. In all three of our home games we produced good football and that is what matters to me."
Atletico's Argentine coach Diego Simeone was satisfied with his team's display.
"We had chances to win in the second half but... we achieved a good result against a great team," he said. "The team performed really well and that's a good sign for the future." (Writing by Tony Jimenez, editing by Ken Ferris)