Didier Drogba spent parts of this match horizontal but, like a good heavyweight, he rose from the canvas to land a hugely significant blow.
Chelsea's defence certainly stood up to be counted, constantly thwarting Lionel Messi. Chelsea face a huge challenge in the away leg but their defensive resilience, Drogba's goal, and Roberto di Matteo's shrewd tactics have given them a chance.
In orchestrating his 10th win in his 13 matches as interim first-team coach, Di Matteo's game-plan was simple but superb. Throw a blue blanket across midfield, stifle Messi and order Ashley Cole and Ramires to defuse the right-sided missile called Dani Alves.
Cole was immense. Ditto Ramires. Gary Cahill took Messi's presence in or near Chelsea's area as a personal affront. Petr Cech was the model of defiance in goal. Drogba, for all the frustration at his theatrics, took his goal well.
"It will go down as one of our best performances," said their captin John Terry, who has played with cracked ribs in recent weeks. "We had to be patient - we didn't touch the ball in the first 10 or 15 minutes. It was a tireless performance."
Chelsea's fans would have settled for parity at the break. They had only 25pc possession, managed only 130 passes to Barcelona's 402, were almost punished by Alexis Sanchez and Cesc Fabregas, were indebted to Petr Cech and their fans chanted "Ole" on the rare occasions that their players managed to build a move.
Yet, they turned around ahead, Drogba striking in the two minutes of injury-time awarded primarily for the amount of time he spent on the floor.
The muscular Ivorian seemed more horizontal than vertical at times, and it became frustrating to watch, even if it did help Chelsea break up Barcelona's momentum.
However, Drogba took his goal well, totally vindicating Di Matteo's decision to start him ahead of Fernando Torres.
Drogba's shot was a shock, partly because it was Chelsea's only one on target in the first half and also because the force had largely, inevitably, been with the vaunted visitors.
The first glance at Barcelona's team-sheet had indicated the scale of Chelsea's task. Messi, Dani Alves, Sanchez, Xavi, Andres Iniesta, Fabregas et al.
This was the team of all the talents, the holders of the Champions League, a side packed with World Cup winners. Chelsea, commendably, refused to let fear seep into their hearts.
In keeping with his stellar status, Messi had kicked off, triggering a meandering Barcelona move.
Barcelona's technical gifts were quickly in evidence, their ease in possession, even when Chelsea triggered their much-anticipated pressing game, looking to squeeze the space around Messi.
'Operation Lionel Taming' had two flaws -- namely that Messi could wriggle out of a straitjacket and that any focus on the Argentinian afforded room for his team-mates.
Sanchez exploited this, darting through, beating the offside trap and lifting the ball over Cech, denied only by the bar.
At that stage, the thought of Chelsea going down the tunnel at the break a goal to the good was the stuff of fantasy.
Compared to the Catalans' rapier-like passing, Chelsea's tactics were far more one-dimensional, more broadsword, mainly looking to release Drogba through the middle.
Cech picked him out early but the Ivorian's first touch was slightly heavy and the moment was lost. Then, Drogba misjudged the ball's trajectory and Carles Puyol nipped in to clear.
Drogba was surrounded by Barcelona players, who sought to trap him. Puyol pushed close, Sergio Busquets dropped back from midfield, even taking a painful knock on the right foot from Drogba.
Chelsea's No 11 moved left after a while, looking to find space behind Alves, who was frequently upfield. Chances came and went for the Catalans. Alves teed up Messi, who glided across the box, seeking an opening, and then letting fly. John Obi Mikel threw himself in the way of the shot.
Then, Cech thwarted Iniesta, and Fabregas wasted a golden opportunity with the follow-up. The tide was mainly flowing towards Cech yet Chelsea resisted these surges in the first half, even springing some counters of their own, famously so in the dying seconds.
Until then, Barcelona kept putting together their triangles, working the ball around blue shirts. When Ramires sprinted through, Puyol calmly took control, rolling the ball back to Victor Valdes, who stroked it to Javier Mascherano. As Ramires changed direction, chasing the ball, Mascherano slid it to Puyol, who worked it forward. So simple. So effective.
Until injury-time, Barcelona's covering was excellent. When Drogba turned away from Puyol, Alves was there to clear. But they could not turn all this possession into real penetration.
Cech, exceptional again, saved from Fabregas. Then Sanchez lifted in a cross from the right, the ball angled back to pick out Messi. The little magician leapt high, meeting the ball with a strong header, directed down to Cech's left. Chelsea's 'keeper did well, tumbling to one side, rescuing his team.
Back came Barcelona again, Messi releasing Fabregas, who dinked the ball over Cech. Cole had read the danger, dropping back on to the line to clear Fabregas.
Such resilience was rewarded when Chelsea seized the lead with almost the last kick of the half. Ramires, capping an outstanding half, raced into the box and squared to Drogba, who beat Valdes.
Having spent periods of the half on the floot, Drogba celebrated by sliding across the grass, saluting the fans like a manic sergeant-major.
The men in black stormed at the blue ramparts in the second half.
Some of Chelsea's defending was magnificent. Some of Cahill's tackles drew standing ovations. As the second-half siege unfolded, he saw off Messi and Sanchez in quick succession.
Barcelona were struggling to find an opening, struggling to break Chelsea's resolve. Fabregas fired wide. Then Cahill continued his repossession work, frustrating Messi. Frank Lampard joined in, nicking the ball away from the dancing feet of Messi.
Guardiola began to dip into his rich reserves, sending on Pedro for the quiet Sanchez.
The game became scrappy, bitty, broken by fouls and bookings, the slowing of the tempo just what Chelsea wanted. Ramires was still unfortunate to be cautioned for a challenge on Messi, the Brazilian clearly targeting the ball.
Ramires refused to be inhibited, soon accelerating down the left until felled by Busquets, who went into Felix Brych's book.
Barcelona kept hunting that away goal. When Messi whipped in a low free-kick, the shaggy hair of Puyol flicked it on but there was Cech saving the day. Barcelona should have scored through Pedro, who hit the post, and Busquets in the final minute but Chelsea held firm.
Another test awaits in Catalonia but Chelsea are refusing to pay homage. (© Daily Telegraph, London)