Barring Hart, City had nobody to match Alonso and Alaba. James Milner came on, giving greater balance to City’s midfield. David Silva darted around to good effect but in the grand scheme of the game’s pressure points, Bayern deserved the three points. Yet it was an insult to sporting justice for Hart to finish amongst the vanquished.

He has rarely played so well for City, his performance up with his display against Borussia Dortmund in 2012 (when Robert Lewandowski and Mario Götze tested him). It added to Hart’s sense of frustration that the catalyst for City’s defeat was a player he once called a team-mate.

In 2010, Hart returned from the World Cup determined to prove himself as City’s No 1, following a fine season on loan at Birmingham City. Boateng joined that season, making 16 appearances in the league as Hart cemented his place as first choice.

Bought from Hamburg for £10 million, Boateng was the type of emerging talent – like Hart – that City hoped would help them develop into a European force. Boateng left for Bayern, netting City £2 million profit, because he felt he was being played out of position, occasionally at right-back, so he leapt at the chance to move to the Allianz.

He has since developed into one of the leading centre-halves in the world, shining for Germany at the World Cup, a mobile figure of defensive defiance for club and country, and he wreaked real damage on his former paymasters, putting City on the back foot in Group E particularly with Roma destroying CSKA Moscow.

Boateng’s goal was just brutal for Hart, whose athletic repelling of Bayern began early. Bayern were enjoying so much possession, creating so many chances that the City goalkeeper had needed all his reflexes.

Hart had done well against Lewandowski before, notably against Dortmund and Poland but he had known the threat came from all angles, including a new one in Alaba, who would have been close to possession of the match-ball by half-time but for Hart.

Hart is hurtling towards a weekend skirmish at the Etihad against Chelsea, who gave him one of his most painful moments of last season, when he gifted Fernando Torres the winner at the Bridge.

It triggered a long debate about whether Hart should keep goal for City, and he was omitted for a few games, and his place as England’s first choice was also brought into question. Hart responded well, working hard in training, and confirming his place for club and country.

This season, though, he has faced another challenge, from Willy Caballero, a keeper highly admired by Manuel Pellegrini from their days at Malaga.

Hart responded again, ensuring his starting place, and then producing this unrewarded performance much to the delight of the City supporters. For 89 minutes.

This was a familiar journey for City fans, who have witnessed the Carlos Tévez warm-up fiasco in a 2011 defeat and also an unexpected win here in 2013. Around 1,500 fans travelled to Baveria, with 2,000 tickets sent back according to City.

Ultimately thwarted, they had arrived in good voice, enjoying the news that their Under-19s had defeated their Bayern counterparts, and then admiring the goalkeeping of Hart.

In between significant, nerve-shredding Bayern pressure, they were able to thrill to a charge from Touré upfield, linking with Samir Nasri before Gaël Clichy’s cross failed to clear the first defender.

For all their gratitude to Hart before the break, City were not shy going forward, putting together their passing moves. Samir Nasri, Touré and Silva were playing triangles, working the ball forward.

With Sergio Agüero on the bench for two thirds of the game, the forward focus was on Edin Dzeko, who had Silva in close support in City’s 4-4-1-1 system. After 12 minutes, Silva slid a through-pass to Dzeko, whose low ball to the near-post was eventually grasped by Manuel Neuer.

But it was City’s goalkeeper by far the busier. Bayern were missing such luminaries as Franck Ribéry, Javi Martínez and Bastian Schweinsteiger with Arjen Robben on the bench until late on but they posed a relentless threat. Early on, Thomas Müller wriggled through, but found only the side-netting.

The danger was always there. From a Juan Bernat cross, Hart did brilliantly to tip over a Müller header. Then Hart saved from Götze, from Alaba, and from Götze again in the second half. Milner replaced Nasri, trying to break up Bayern’s midfield control.

Still, City had their chances. From a Jesús Navas cross, the diving Silva headed wide. Hart still had the occasional wobble, spilling a shot from Rafinha but City were holding firm. Pep Guardiola responded by bringing on Robben, whose overdeveloped sense of gravity’s pull was seen again with a tumble when challenged by Fernandinho.

Bayern were trying everything. Boateng’s 30-yarder would have beaten a lesser keeper but Hart pushed the strike away. But Bayern would not give up and Boateng’s right-foot shot from inside the box, taking a nick off Götze, gave Hart no chance. Guardiola’s wild celebrations spoke of Bayern’s relief.

City tried to rescue a point, and Agüero poked a shot just wide, but the final whistle soon sounded.

Hart departed with his head held high but his excellence unrewarded