MANCHESTER: Manchester United battled back after conceding a fourth-minute goal to grind out a hard-fought 2-1 victory over VfL Wolfsburg at Old Trafford on Wednesday, the English side's first Champions League win of the season.

There was huge pressure on United after they lost to PSV Eindhoven in their opening Group B match two weeks ago and their night got off to the worst start when Daniel Caligiuri opened the scoring for the well-drilled visitors after some poor defending.

United, who came from behind to beat Wolfsburg 2-1 exactly six years ago to the day, followed the same script with Juan Mata equalising with a 34th-minute penalty, while defender Chris Smalling proved to be the unlikely match-winner when he slid in to score his first goal of the season after 53 minutes.

United manager Louis Van Gaal, who said before the match United had to win all of their home games to have any chance of making it through to the last 16, told BT Sport it was a hard-earned victory.

"It was very difficult because they scored (so early) but then we did very well and created a lot of chances, but we didn't finish...

"we were suffering. A lot of players are very tired because of the accumulation of matches, but still, we did not give much away."

Wolfsburg coach Dieter Hecking said: "We had a good start to the game. Midway through the first half we lost a bit of control and they had the chances to level."

With CSKA Moscow beating PSV Eindhoven 3-2 in Russia, the four teams are all level after two matches. CSKA Moscow host United and Wolfsburg are at home to PSV in Matchday Three on Oct.21.

United started the match buoyed by going top of the Premier League at the weekend, but they were reeling after Wolfsburg struck to take the lead after a six-pass move.

United were guilty of woeful defending as Antonio Valencia played Caligiuri onside and he picked his spot to beat David De Gea.

Wayne Rooney should have equalised for United after 26 minutes after fine work down the right from Anthony Martial, but the United skipper, who had a poor game in attack, blasted the ball high and wide when it looked easier to find the net.

They drew level when Mata sent goalkeeper Diego Benaglio the wrong way with his penalty after Hungarian referee Viktor Kassai ruled scorer Caligiuri handled in the box.

Mata was instrumental in setting up United's second goal as well, providing the final pass with a creative, backheeled flick that allowed Smalling to slide home his first goal of the season after 53 minutes.