For Chelsea, it was difficult to imagine a more perfect evening. It had been easy to worry about the awkward nature of Atlético Madrid’s threat but the manner in which they contained the Spanish league leaders offered the latest evidence of the resolve and discipline that Thomas Tuchel has brought to the club. Chelsea caught a break in the first half when the score was 0-0, César Azpilicueta putting his hand across Yannick Carrasco inside the area as the last defender and not being penalised. It looked like a penalty and a sending-off. But Atlético could get little else going and it was difficult to remember Édouard Mendy having to make a save until his stoppage-time tip-over from João Félix. By then, it was over. The thick blue line in front of him was taut and unyielding and, in front of that, there was N’Golo Kanté, who had one of those nights for which the old joke was invented. Tuchel had Mateo Kovacic in midfield with Kanté either side. One minute, Kanté was zipping back to close the door on Atlético; the next, he was surging past red and white shirts to tee up chances. Chelsea’s celebrations were hearty upon the full-time whistle and who could blame them? After four successive defeats in the Champions League last 16, they had finally advanced and nobody will relish drawing them. In 13 matches in all competitions under Tuchel, they have conceded just twice, with one of them being Antonio Rüdiger’s freak own goal at Sheffield United. Moreover, they are not looking like conceding. The way that they compress the space around attacking players, often hunting in coordinated packs, and give up so little inside their penalty area is hugely impressive. There is a strong-arm physicality about their central defensive three, which is personified by Rüdiger, although he embraced the darker arts in the 81st-minute incident that led to a red card for Stefan Savic. Up for a corner, Savic aimed an elbow into Rüdiger’s chest – it was a sly dig – but the Chelsea player went down as if poleaxed. What about Chelsea at the other end? This was no rearguard triumph, rather the kind of return that they hoped for when they spent so heavily on reshaping their attacking options last summer. With Mason Mount suspended and Tammy Abraham injured, Tuchel started with Hakim Ziyech and Kai Havertz either side of Timo Werner and all three had eye-catching moments, not least when they combined for the opening goal. Atlético had plenty of players forward when Chelsea cleared a cross into their area and, suddenly, Kieran Trippier was on his heels and Havertz was striding away from him. Diego Simeone, who provided quite the sideshow on the touchline, lost himself in a funk. The Atlético manager could see what was about to happen. Havertz played in the overlapping Werner and his low cross invited Ziyech to finish low past Jan Oblak. The first leg had been claustrophobic, shaped by Atlético’s reluctance to take risks and the impression that they would be happy with a 0-0. They did not get that, thanks to Olivier Giroud’s spectacular overhead kick, and so they had no choice here. They had to try to come out. Simeone asked his players to squeeze high at the outset and they howled in vain for a free-kick to the right of the area when Rüdiger barged into Luis Suárez on 23 minutes. The real controversy would come moments later. The former Liverpool striker tried to play in Carrasco only for Azpilicueta to read his intentions and move to usher the ball back to Mendy. Only he left the pass short and, with Carrasco clean through, he grabbed at him. When Carrasco went down, the penalty felt inevitable and so did the red card, given that Azpiliceuta had made no attempt to play the ball. And yet the foul was not given. Mysteriously, VAR did not check the incident. How Chelsea finessed the reprieve. Shortly after Havertz was booked for catching José María Giménez with an elbow in an aerial challenge, he ignited the move for Ziyech’s goal. Before that, Werner had gone close with a shot on the spin and, after it, Chelsea were liberated. It was lovely to see Havertz enjoy himself on the ball. His touch was loaded with assurance while his rangy style seemed to give him an extra half yard of pace. Ziyech was all quick feet and incisive actions and he released Werner early in the second-half; it took a fine block from Oblak to deny him. Werner’s movement was sharp throughout. Ziyech also extended Oblak with a curler for a top corner. Chelsea largely restricted the Atlético dangerman, Félix, and they turned the screw in the closing moments. One substitute, Callum Hudson-Odoi, shot weakly at Oblak on the break but, after a similar move, another one, Emerson, picked out a bottom corner. It was no more than Chelsea deserved.