The German produced two clinical finishes after the break as Arsenal accelerated to a 5-0 victory that sent a powerful message to Liverpool and Manchester City.
Havertz took 10 appearances to mark his first Arsenal goal and for those first few months in north London the player who scored the winner for Chelsea in a Champions League final looked like a player struggling for identity.
But those difficult times now look behind him and 12 goals in all competitions looks a decent return while his all-round play gives Arsenal's attacking flexibility.
"He deserves it. He's been outstanding since he's come in. You don't realise how good he is until you play with him," Ben White, who also scored twice, said.
Manager Mikel Arteta showed loyalty to Havertz earlier in the season and is now being richly rewarded with the former Bayer Leverkusen striker unleashing his full potential.
"His overall contribution in every phase of play was tremendous," Arteta said. "When you add the two goals he scored and some of the link-up play that he had in big moments, it was a great performance."
While Manchester City still have a fourth successive Premier League title in their own hands, the nature of Arsenal's demolition of Chelsea piled on the pressure.
Liverpool are three points behind Arsenal while City are four points back with two games in hand, although Arsenal's huge goal difference advantage is effectively worth another point.
With Liverpool at Everton on Wednesday and City at Brighton on Thursday, Arteta will be watching and hoping for any slip-ups as his side begin to prepare for Sunday's seismic north London derby at Tottenham Hotspur.
"We have to do our job. Now we have to wait and see (for Liverpool and Manchester City's results)," Arteta said.
"We have a lot of games coming up. Let's enjoy tonight and let's go back to work."
While Arsenal will head into the final weeks on a high, Chelsea's recent revival appears to have run out of steam.
While they were without Premier League joint top scorer Cole Palmer and had a re-shuffled back four because of injuries, their second-half capitulation was worrying.
They remain ninth and their hopes of qualifying for Europe as a consolation for a mediocre season are receding.
"We were not aggressive and we did not concentrate in situations where it is easy to find the solution. That is why we're so disappointed," manager Mauricio Pochettino said.
"It is difficult to talk about objectives. If we compete like Saturday (in the FA Cup semi-final defeat by Man City), OK. But if we compete like today, do I think we deserve to go into Europe? I think in this way, no."
