Chelsea secured their second win of the season, but they were made to work for it by a well-organised and disciplined Leicester City.
Nigel Pearson's newly promoted team were determined to avoid their fate of fellow Premier League returnees Burnley. And they very nearly managed it.
It took a goal of exceptional class to break Leicester's resistance, Diego Costa's second in as many games.
Oscar's perfectly judged through-ball found Branislav Ivanovic, the Serbia defender turned sharply and sent his markers sprawling, then teed up Costa with a fine pass.
The Spanish international made a mess of his first touch, but pounced to redeem himself with his second.
They are already falling in love with him at Stamford Bridge.
A second strike from Eden Hazard confirmed the victory.
Mourinho, unsurprisingly, stuck with the 11 men who had dismantled Burnley on Monday, but he did made a change on the bench.
Fernando Torres, linked with a move to Roma, wasn't even named as a substitute. His miserable time at the club, surely, is drawing to a close.
Costa's prolific start has only emphasised how poor the former Liverpool man has been since his £50-million ($103m) transfer.
Pearson made two changes, one by choice with the fabulously named Jeff Schlupp chosen above Anthony Knockaert, one by necessity with the injured Danny Drinkwater replaced by former Southampton captain Dean Hammond.
Sadly, Hammond himself would leave the game early, clutching his leg.
Chelsea found the going tough from the start.
Though they piled the pressure on their guests, they failed to put a single shot on target in the first half, their best effort coming from Costa after 36 minutes, deflected over the bar by the redoubtable Wes Morgan.
Leicester were excellent, well organised and hardworking.
With two defiant rows of four, they squeezed together whenever Chelsea approached, reducing the space and restricting their tormentors with a degree of comfort.
Pearson has drilled his men well and it's hard to see them being dragged into a relegation battle.
They made their own chances too, primarily when Eden Hazard's willingness to track back was exposed and Riyad Mahrez was given the room to run at Cesar Azpilicueta.
On the touchline, Mourinho looked distinctly unimpressed.
Whatever he said at half-time worked.
First, Oscar rattled the post with a long-range effort, then Ivanovic's header was clawed away from the top corner by goalkeeper Kasper Schmeichel.
Moments later, Andre Schuerrle curled a fine effort just over the bar.
But it was Leicester who came closest to scoring when David Nugent found himself one-on-one with Thibaut Courtois, only to be denied by the quick-witted Belgian.
That save will have won him the confidence of the Chelsea supporters, but there was more to his performance than that one moment.
Courtois was indomitable in the air, snatching lofted crosses out of the air in a manner reminiscent of a peak David Seaman, the master of that particular art.
Petr Cech is left to languish on the bench, and he's clearly unhappy, but it's not hard to see why Mourinho has backed the young Belgian shotstopper.
With Leicester's best chance spurned, Chelsea's breakthrough came in the 63rd minute, a reward for their application if nothing else.
Leicester tried to rally, but the more they pushed forward, the more gaps they left behind for Chelsea to exploit.
With 13 minutes to go, Hazard finished the game, weaving in from the left and slipping a shot underneath Schmeichel, via the ankle of Morgan.
Two from two for Chelsea and the favourites have found their groove.
Ominous signs for the rest of the Premier League.
This article was first published on August 25, 2014.
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BLOW BY BLOW
55 min David Nugent is clean through with only Thibaut Courtois to beat, but the Belgium goalkeeper saves the day. He's out quickly, spreads himself and Nugent's shot bounces off his leg and away. How valuable will that prove?
63 A splendid goal! A great ball from Oscar finds Branislav Ivanovic, who turns sharply, finds space and then tees up Diego Costa for the finish.
77 Eden Hazard cuts in from the left and fires home the second goal off a cruel deflection.
80 What a reception for Didier Drogba on his return to Stamford Bridge. The fans are on their feet, Roman Abramovich is on his feet. A hero returns.