Atletico Madrid 0-1 Chelsea: Olivier Giroud scores brilliant bicycle kick as Blues win ‘away’ leg

The ball found the net at 67 minutes and 56 seconds. At 70 minutes and 45 seconds, Chelsea were allowed to celebrate. They had scored an away goal in a neutral stadium.

That is modern football for you, but nobody on the flight back from Bucharest would have been complaining. Justice was done. The better, the more ambitious team, were victorious. Dour, dogged Atletico Madrid lost. Now Chelsea have a vital advantage going into the second leg. They will need it, too. Mason Mount and Jorginho will be missing, suspended, and Atletico are dangerous when wounded.

Yet this was a huge win, for Chelsea and their manager Thomas Tuchel. For match-winner Olivier Giroud, too. He was Tuchel’s first choice as striker in his first game but has not kept the position. He might, after this. His hold-up play was excellent and his goal — well, it was a beauty. The sort of goal that very much deserved to win a nip-and-tuck encounter. It was a moment of sheer class in what was otherwise a cussed, niggly affair.

Olivier Giroud scores for Chelsea against Atletico Madrid in the Champions League round of 16 on Tuesday evening

The French striker produced a stunning overhead kick after the ball popped up into the air in the Atletico Madrid penalty area 

Both sets of players watch on as Giroud’s (3rd left) acrobatic effort makes its way into the bottom left corner of the goal 

Giroud celebrates with team-mates Mason Mount (R) and Callum Hudson-Odoi (L) after breaking the deadlock in Bucharest

The 34-year-old (2nd right) is congratulated by his entire team after scoring a crucial ‘away goal’ in the second half

So why the confusion? Well that was a very modern kerfuffle, too. Those who expected VAR to make black-and-white decisions had not reckoned with a rulebook that remains 50 shades of grey. Was the ball played deliberately or accidentally? The answer to that question decided this match.

Dogged resistance is Atletico’s core strength, so it was a surprise that what was pretty much a hopeful cross from Marcos Alonso caused them to crack. Mount was in there, hustling, and it unsettled defender Mario Hermoso. The ball spun off to Giroud, who buried it with a beautiful overhead kick. Atletico’s Joao Felix had tried one like it earlier, but without success.

Alas, a linesman’s flag was up. Chelsea despaired. But VAR makes checks without bidding these days. So referee Felix Brych paused the restart while his colleague Marco Fritz had a look. And a look. And another look. Heaven knows how many times he peered into the soul of Hermoso, seeking clues to his motivation. Close to three minutes passed. Various players, mostly in stripes, tried to apply some local pressure. Brych merely stepped out of earshot, kept his cool.

Eventually, enlightenment came. Hermoso’s intervention had been judged a deliberate attempt to play the ball — which it probably was. He had therefore played Giroud onside. The goal was awarded.

Chelsea celebrated as a team, and VAR be damned. They celebrated as if the goal had been scored three seconds, not three minutes, ago.

And Atletico? They reverted rather swiftly to tetchy type. Well, one of them did. What would cause Antonio Rudiger to react so furiously to what at first appeared a pretty meaningless clash with Luis Suarez? Ah, it was that sneaky pinch on his inner thigh, caught on camera in the replays.

Suarez was later booked for a foul on Andreas Christensen. He will not be banned from the second leg, though, meaning Atletico’s greatest, most irritating threat remains.

Still, after a very shaky start, this was a strong performance from Chelsea. They saw a lot of the ball and could have grown frustrated with Madrid’s massed ranks, instead holding firm to beat a team who have dominated LaLiga this season.

Credit in a supporting capacity, too, to Tuchel’s predecessor Frank Lampard. His run of six Champions League games unbeaten to here is Chelsea’s best group-stage performance since 2014-15, creating a bedrock of capability. Whether he would have pulled this off given the changes in personnel and formation made by Tuchel is another matter.

For it was tight. It always is when Atletico are playing, whether in Madrid, Bucharest or anywhere. That is their style. A low block, 11 behind the ball, crowd and defend the middle, smother the creators, pick a player who is weak in possession and swarm around him. They are masters at it.

Atletico striker Luis Suarez clashes with Chelsea centre-back Antonio Rudiger after he appeared to pinch him on the leg

Chelsea manager Thomas Tuchel gives Giroud a pat on the back after substituting him in the closing stages of the match

So Chelsea will have been pleased with their possession statistics and the chances forged but, until the goal, little challenged Atletico’s game plan. They are used to playing and organising without the ball, used to the odd moment when their goal is under siege.

Equally, they are content to exist that way, confident they can resist. Chelsea grew into the game, but if a team could have a human face, Atletico’s would be expressionless, a blank stare of calm defiance. And they are happy that way.

The game started badly for Chelsea with a first-minute booking for Mount. Felix took a tumble and referee Brych thought it was more Mount’s work than that of Cesar Azpilicueta.

Neither looked worthy of a caution but Brych awarded one anyway, meaning Mount misses the return leg. Jorginho fouled Felix in the second half and will now sit by his side.

Madrid manager Diego Simeone shows his frustration after his side missed a chance to level the scores in the European tie

Nothing came of the free-kick but as Chelsea tried to recycle the ball, goalkeeper Edouard Mendy took a heavy touch and almost let in Felix. Fortunately, his touch was equally lacking in subtlety, taking the ball away from danger.

One of Madrid’s strengths is the ability to conjure opportunity from hard graft and in the 14th minute Chelsea almost fell foul of that.

Suarez somehow managed to muscle Rudiger and Alonso off the ball, turning and cutting towards goal from the right. His low cross found Thomas Lemar at the far post but the Frenchman could not turn it into the unguarded net.

Yet Chelsea slowly grew in confidence and created the better chances. Mount nutmegged Marcos Llorente after 39 minutes to set up Timo Werner, who took the wrong option, trying a shot from an acute angle when Giroud was better positioned, and Jan Oblak saved.

The Chelsea players celebrate after the referee’s full-time whistle confirmed their huge first leg victory at the National Arena

By half-time, the numbers favoured Chelsea. Atletico had not been kept this quiet in 45 minutes of Champions League football since facing Real Madrid in 2017, the night Cristiano Ronaldo took them apart.

Chelsea have not got a player with Ronaldo’s eye for goal, which is perhaps why Atletico were content to concede so much possession, but even the great showman would have been proud of Giroud’s decider.

He would respect another of his records, too — 15 goals in 16 starts for Chelsea in Europe.

Sure, there is much work to do. But this result shows Atletico are far from invincible, for all their stubbornness. This is the 14th time Chelsea have won the first leg of a European knockout tie away — and the other 13 times they have progressed. However, awkward the opposition, that is a start.

Scroll down to see how it all unfolded with Sportsmail’s live runner.