Struggling Liverpool looked set for a morale-boosting win in Lyon when substitute Ryan Babel opened the scoring in the Group E match with a superb 25-metre strike.
But Argentine striker Lisandro Lopez grabbed the equaliser in the 90th minute and Liverpool now have to win their last two games -- and hope Fiorentina drop points against now qualified Lyon -- if they are to avoid a first-round exit.
Lyon top Group E with 10 points from four matches followed by Fiorentina (9), Liverpool (4) and Debrecen (0).
"Do not worry, we will play properly because it is our goal to finish top of the group," Puel told reporters.
"It is important for us to get a good result in Florence, and it will give Liverpool a chance."
(Writing by Julien Pretot in Paris; Editing by Kevin Fylan)