The Blues were crowned Premier League champions after Michy Batshuayi stepped out of the shadows and provided the pivotal late goal that handed Chelsea the title.
Batshuayi had not scored in the league since August but slid to meet a Cesar Azpilicueta cut-back in the 82nd minute – just moments after coming off the bench – to ensure the Blues secured their fifth Premier League crown.
It looked as though Antonio Conte’s side might be forced to delay their celebrations as they were frustrated for long periods by the resilience and organisation of Tony Pulis’ West Brom.
But the mood changed and the title was won with eight minutes to spare as substitute Batshuayi ended a scrappy passage of play by steering a finish high past Ben Foster.
The final whistle sparked jubilant celebrations among Chelsea’s fans, and manager Conte was tossed high into the air by his squad.
Tony Pulis had warned his side would do their “damnedest” to make Chelsea work hard for the prize and Rondon fired an early warning, beating David Luiz to a header that forced Thibaut Courtois to tip behind with just a minute on the clock.
Cesc Fabregas, who starred in the win over Boro that put his team-mates on the brink, was soon plotting again, lofting an exquisite pass forward that Pedro miscued, before delivering an inswinging free-kick that just evaded the encroaching Gary Cahill.
Chelsea then had strong shouts for a penalty, on a night where Oliver made a number of controversial decision, as Pedro’s cross struck the outstretched arm of Chris Brunt. Referee Michael Oliver was unmoved with play continuing.
While Chelsea were dominant in possession, the hosts carried a threat on the break, which could have counted had James McClean’s pass not forced Rondon to check his run.
Again, Chelsea had another strong shout for a penalty after Hazard tumbled under Jonny Evans’ challenge, again Oliver was unmoved, and Chelsea continued to be frustrated by the Baggies defence.
Chelsea started the second half with sharpened focus, Ben Foster brilliantly pushing away a Victor Moses drive and Claudio Yacob was forced to clear on the line when Hazard jinked at the byline as the breakthrough remained elusive.
Costa was taunted by the home fans as he slipped in the box while attempting to swivel and an Albion side growing in confidence so nearly punished Chelsea, Rondon breaking free only to be denied by a desperately backtracking Azpilicueta in the 71st minute.
Conte had watched on with a grimace as Rondon raced away and Nacer Chadli had a glorious opportunity minutes later, only to fire wide.
The Chelsea boss threw on Willian and Batshuayi for Pedro and Hazard as the half entered its final stages and a man seemingly surplus to requirements picked his moment, tucking beyond Foster as his team-mates exorcised demons of last term’s underachievement with a fifth title of the Roman Abramovich reign.
Having redeemed themselves, the Blues can now put the misery of last season behind them and bask once again in glory. All that remains is securing the FA Cup trophy against Arsenal at the end of the month, gifting Antonio Conte a rare domestic double.