"I'm working hard and you are starting to see the results," the Swede, who missed a penalty in Saturday's 2-0 Serie A defeat at Cesena, told Sky television. "It was a wonderful night."
The gangly yet skilful striker has always flattered to deceive on the biggest stage, his switch from Inter Milan to Barcelona last year being symptomatic of his ill-fortune as his old club then went on to break their Champions League hoodoo.
He waltzed back into the San Siro like he had never been away, Milan fans far too used to signing ex-Inter players to even think of giving him anything other than a great welcome.
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Their cheers soon turned to worried frowns, though, as Milan put in a woeful first-half performance in their Group G opener with Ibrahimovic hardly having a touch partly through his lack of movement and partly because of a dearth of service.
Auxerre, third last term but yet to win in Ligue 1 this season, had the best chances before the break with Adama Coulibaly heading against the bar and Steeven Langil wasting a great opportunity when Milan were completely outnumbered.
"With their counter-attack it went in our favour," new Milan coach Massimiliano Allegri told a news conference after the Rossoneri's first home European win in almost two years.
"Second half they dropped off and we played better. Ibra had a great second half because he played more with the team."
Allegri, making his Champions League debut like counterpart Jean Fernandez, stood in his technical area with arms folded in the first period but his halftime team talk worked.
Kevin Prince Boateng, who bizarrely signed on loan for Milan last month having been bought by Genoa from Portsmouth the same day, came on as a first-half substitute for injured captain Massimo Ambrosini and soon began to make his presence felt.
Milan have been crying out for a midfielder who can break into the box for years and the Ghana World Cup player obliged by storming into the area to flick on Ronaldinho's 66th minute cross and allow Ibrahimovic to prod home at the near post.
Brazilian Ronaldinho, also anonymous in the first half, was provider yet again three minutes later when he burst up field and played in Ibrahimovic for a cool finish into the far corner.
Milan's new hero held his arms out wide in a familiar goalscoring pose, a clothes horse for the fast-approaching team mates who clung to him in ecstasy.
Auxerre were too much in awe of their San Siro surroundings like their fans taking photographs of the famous stadium before kick off and if they had shown more belief they could have won.
"It's difficult to swallow," Fernandez said.
"The frustration is that towards the end of the first half we had great chances to score. There was just a little lack of experience when we had men over."
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