LONDON -- All through the second half, there was a sense of pressure mounting, of Paris St-Germain's belief ebbing and Chelsea's correspondingly swelling. And then, with four minutes remaining, a Cesar Azpilicueta shot scudded across the box and was deflected into the path of Demba Ba, who forced the ball over the line from six yards. It was Chelsea's day to reach the Champions League semifinals, doing so via away-goal tiebreaker after a 3-3 aggregate draw.
It wasn't the prettiest of goals, but it didn't matter. Off went Jose Mourinho charging down the touchline as he had 10 years ago at Old Trafford when he announced himself to the English game with his exuberant celebration of Porto's late winner over Manchester United in the last 16 of the Champions League.
There was no knee-slide this time, but then Mourinho is 51 now - and perhaps he is becoming more used to success. This is, after all, his fifth Champions League semifinal in a row with three different clubs.
Somehow, amid the celebrations, Mourinho ended up with a hand either side of Fernando Torres' head, his mouth next to his ear. "It was not a celebration," Mourinho said afterwards. "It was to tell the players how we had to play the last 10 minutes. At that moment they wanted to celebrate, to think that the game was over. They forget that we had three or four minutes plus injury time to play. We couldn't keep playing the way we were playing. I had to go there to tell Torres and Schurrle how we had to play."
WATCH: Mourinho sprints length of field after Ba's goal
PSG still forced a couple of late corners, and Petr Cech made a vital save low to his left to keep out an effort from Marquinhos, but Chelsea, having hit the bar twice in the space of a minute early in the second half, deserved its victory.
After the first leg defeat, Mourinho seemed scornful of his entire forward line, speaking of the need for "real forwards."
"Maybe Jose doesn't have the strikers he wants," said Ba. "I think he has three great strikers. Lots of clubs would like us three."
Asked pointedly whether Ba's goal had been a "real striker's goal," Mourinho seemed to duck the question: "I'm happy for him," he said. "He's a good guy, a good professional and a good man for the group."
All three were on the pitch at the end as Mourinho threw more and more attacking players at the problem. There was no great sophistication,but the ever intensifying barrage played on PSG's very evident nerves.
Its manager Laurent Blanc, among others, had spoken of the need for a statement victory to confirm themselves as a European power and after the first leg seemed to assume this would be it. As it was, it produced a tactically incoherent display lacking in drive or character and was ultimately deservedly beaten.
"We managed the first 25 minutes very well and conceded a goal when least expected it," Blanc said. "We lacked a bit of fluidity but might have been able to score on the counter. Over the two matches there was very little to choose between the two sides. Ultimately Chelsea's greater experience at this level proved the difference."
For the first quarter of the game, Chelsea posed little threat, but even in those early stages it was hard to know exactly what PSG was trying to do. There was a diffidence when it went forward, some players sitting back as though concerned to commit too many men to the attack, which diminished the potency of those forward thrusts, yet at the same time there seemed no great urge to kill the game or to play for a 0-0 draw.
Once Chelsea had pulled one goal back, with substitute Andre Schurrle - on for the injured Eden Hazard - stroking in David Luiz's flick from a Branislav Ivanovic throw-in, PSG's panic was obvious. Thiago Motta was scathing.
"We came to Stamford playing in a certain way, but we didn't," he said. "From the chaos, Chelsea scored twice."
It was manifest both in the way PSG dropped deeper and deeper - Blanc accepted his side had dropped too far, inviting pressure and the sort of penalty-box pinball that ultimately undid the Ligue 1 leader, and in a moment of wastefulness in front of goal that will haunt Edinson Cavani.
The Uruguay striker's touch to take pull a Yohan Cabaye pass into his path was magnificent, but as Cech fell to his knees, apparently accepting the situation as lost, Cavani shot over. Twelve minutes remained at the stage and a PSG goal would surely have been decisive; as it was Chelsea could come again.
"The players followed our plan, our ambition," said Mourinho. "We win or we lose, but we make sure we are without energy to go home. We were lucky, because we had the result we fought for. If for some reason we hadn't scored that last goal or if they had scored from the last corner, I think everybody at this club would still have been proud."
Whatever else has gone wrong this season, whatever failings there have been in Chelsea's pursuit of the Premier League title - which might yet be successful - Mourinho retains a remarkable capacity to win key games almost by force of will. It's a trait PSG was desperately lacking.