Luis Suarez played the role of hero and villain as his 97th minute equliser for Liverpol damaged Chelsea's Champions League qualification ambitions but the Uruguyan's bite on Branislav Ivanovic could spell an end to his season.
Oscar headed the visitors ahead but the half-time introduction of former-blue Daniel Sturridge swung the momentum back Liverpool's way as he levelled seven minutes after the interval.
Suarez's handball had seemingly allowed Hazard, one of six nominees for the PFA Player of the Year award, to score the winner from the penalty spot as Chelsea headed to a welcome win ahead of their Europa League semi-final first against FC Basel, but Suarez had the final say, heading home from Sturridge's cross.
But the ex-Ajax's forward's apparent bite on Branislav Ivanovic cast a shadow over the afternoon for Brendan Rodgers' side, who could be without the Uruguayan for the rest of the season.
The 26 year old was banned for seven matches in 2010 after biting Otman Bakkal and a similarly lengthy ban awaits for Suarez, who continues to be embroiled with controversy.
With Liverpool's European hopes having faded following one win in four games, Rodgers' side were merely playing for pride against a Chelsea side who were looking to maintain their place in the Premier League top four.
Returning manager Benitez was given a good reception from the Anfield crowd, as the Spaniard made his first return to Merseyside as a manager since his departure in 2010 and his team made the perfect start as Oscar headed home from Juan Mata's corner.
David Luiz, fresh from a stunning strike against Fulham in mid-week, almost made it two as Pepe Reina fumbled his initial free-kick, but the Liverpool keeper kept it out before the ball could cross the line.
Suarez tested Petr Cech in a rare first half effort for The Reds, but after the half-time introduction of Sturridge, the hosts sprang into life.
Sturridge laid on a pass for Steven Gerrard who was excellently denied by the legs of Cech, before the England striker's rasping drive rattled the post.
But the home side were level seven minutes after the break as Stewart Downing found Suarez, whose first time cross picked out Sturridge to tapped home.
However, parity lasted for just five minutes as Suarez was adjudged to have handled in the penalty area from Mata's corner, allowing Hazard to put the Blues back in front as he sent Reina the wrong way.
Despite his assist for the earlier equaliser, Suarez's frustrations boiled over as he appeared to bite Ivanovic after a coming together between the two players, an incident not see by referee Kevin Friend and which could be punished by a lengthy retrospective ban.
Jonjo Shelvey should have grabbed a point but only found the side-netting but as Chelsea seemed to be heading into third, Suarez popped up to nod past Cech, a contribution that will be questioned after an earlier bite on Ivanovic which went unsanctioned.