Second-placed Arsenal thought they had won it when Dutch striker Robin van Persie slotted home in the eighth minute of injury time only to see Dirk Kuyt reply from another penalty with the last kick of the game.
The 12 minutes added on for treatment of a head injury to Liverpool's Jamie Carragher were a complete contrast to normal time, which featured precious few chances.
"It was difficult for us to create chances because they defended very deep. Overall they defended well, like most of the Premier League teams that come here, they don't really come out," manager Arsene Wenger told reporters.
"We will have to give everything to the last game of the season and see if it is our year or not. It is about winning games. We are on a 15 match unbeaten run but recently we have not taken enough points."
Arsenal dominated possession in the first half but Koscielny's header from a Van Persie corner was the closest they came to breaking down a dogged Liverpool defence.
But four minutes later, Liverpool replied when Emmanuel Eboue fouled Lucas Leiva and Van Persie's fellow Dutchman Kuyt, who on Saturday extended his contract until 2013, equalised.
"I don't think it was a penalty. Lucas stopped Eboue's run to go to the ball, it is no penalty. Eboue goes for the ball he doesn't go for the player," said Wenger, who was seen exchanging angry words with Liverpool manager Kenny Dalglish after the final whistle.
Dalglish praised his side's resolve after Fabio Aurelio had earlier been withdrawn with a hamstring problem and striker Andy Carroll also left the pitch in the second half with an injured knee.
"I don't think there is any team anywhere that showed the attitude that we showed today," Dalglish told reporters.
"I thought one (of the penalties) was right and one was wrong, you can make up your mind which is which."
