Departing captain John Terry led his Chelsea champions to a 4-3 victory over Watford, scoring the first goal on an evening of celebration, fireworks and streamers rather than vintage football at Stamford Bridge.
Terry, who is leaving this season after 22 years with the club, hooked home a loose ball from a Willian corner in the 22nd minute. The defender has scored in 17 consecutive Premier League seasons.
But the former England captain was at fault for the equaliser when barely two minutes later he back-headed a ball he should have cleared, sending it straight to Etienne Capoue for an easy headed goal.
Chelsea had won the title with a 1-0 victory at West Bromwich Albion on Saturday, so today's game was more about enjoying the moment with the fans and giving those who had not figured too often in the season a chance to shine.
Chelsea manager Antonio Conte, hailed by the crowd with chants of "Antonio, Antonio", made nine changes from the West Brom game, mindful also of the FA Cup final less then two weeks away. Although the makeshift side looked frail at the back, they commanded the midfield and were always dangerous going forward.
Spanish defender Cesar Azpilicueta put Chelsea ahead again in the 36th minute and striker Michy Batshuayi, Diego Costa's understudy, followed his goal at the weekend with Chelsea's third today, four minutes into the second half.
Watford put a brief damper on fans' celebrations with Daryl Janmaat dribbling through for Watford's second goal and substitute Stefano Okaka equalising in the 74th.
But when substitute Cesc Fabregas put away the winner in the 88th minute, the stadium erupted once again in song for Conte, for Terry and for a title that had looked out of reach after a 10th-place finish last season and a shaky start last autumn.
Watford's Sebastian Prodl was sent off in injury time after a reckless challenge on Pedro brought a second yellow card from referee Lee Mason.
But that was only one low point in an entertaining and committed performance from 16th-placed Watford, who never gave up despite having little to play for with just one game at home to Manchester City to go next weekend.
"At this stage of the season I like to see this type of game," Conte said. "It's fun to see teams score three and four goals... but only at this stage of the season."
Fireworks lit up the sky in south-west London as Mason blew the final whistle while blue-and-white streamers rained on the pitch.
The players and their hugely popular Italian coach ran a lap of honour, the besuited Conte jumping and dancing with his charges to celebrate a first English title in his first season in charge.
Chelsea could reach 93 points with victory at home to relegated Sunderland next weekend and Conte's side have the chance to win the double when they meet Arsenal in the FA Cup final at Wembley on May 27.
"The FA Cup final you start to play 10 days before... I have a plan in my head to play the final," Conte said.
"At the moment I have 13 or 14 players who deserve to play the FA Cup final who are in very good form. I have 13 days to make my decision."