Gylfi Sigurdsson took advantage of poor defending to score the Welsh club’s winning goal in the 72nd minute. United captain Wayne Rooney had tied the match after Ki Sung-yueng opened the scoring.
“We never played as a team, that is our error,” van Gaal told BT Sport television. “But I think we have to always keep the head up and use the second step in our process better than we have done today.”
In other games, Arsenal and Tottenham both scored injury-time goals to start the season with wins.
|Swansea City midfielder Ki Sung-yueng celebrates his goal against Manchester United on Saturday. (AFP-Yonhap)|
Aaron Ramsey gave Arsenal a 2-1 home victory against Crystal Palace, which had gone ahead on Brede Hangeland’s first-half header before fellow defender Laurent Koscielny equalized for Arsenal just before the break.
In Mauricio Pochettino’s first game in charge of Tottenham, Eric Dier scored in stoppage time to secure a 1-0 win at West Ham.
There were mixed results for the Premier League newcomers. Queens Park Rangers, which made an instant return after a season in the second tier, lost 1-0 at home to Hull. But Leicester, which has been away from the elite for a decade, earned a point by drawing 2-2 with Everton.
Sunderland and West Bromwich Albion, who both flirted with relegation last season, opened the new campaign by drawing 2-2. Aston Villa, whose owner Randy Lerner is trying to sell the club, began with a 1-0 win at Stoke.
Defending champion Paris Saint-Germain earned its first win of the season in the French league by defeating Bastia 2-0, but lost star striker Zlatan Ibrahimovic to an injury.
Ibrahimovic had to come off after just 15 minutes with an apparent abdominal strain, but Lucas Moura and Edinson Cavani provided goals in his absence.
Lucas got a cross from Gregory Van der Wiel to volley into the bottom corner from a tight angle in the 26th minute. Cavani doubled the lead by controlling a long ball from Marco Verratti before firing home in the 57th.
PSG has four points from two matches after drawing 2-2 with Reims in its opening game last week. The game was marred by an incident after the final whistle, as Bastia striker Brandao waited for Thiago Motta in the tunnel and head-butted the PSG midfielder, leaving him with blood running down from his nose.
Borussia Dortmund defeated third-division Stuttgarter Kickers 4-1 in the first round of the German Cup on Saturday, while Bundesliga side Stuttgart lost 2-0 at second-tier Bochum.
With the exception of Stuttgart’s loss to Bochum, the second division’s early leader, there were few surprises.
Borussia Moenchengladbach and Hannover had 3-1 victories over fourth-tier sides Homburg and Astoria Walldorf, respectively, and Hertha Berlin beat fourth-tier Viktoria Cologne 4-2.
Cologne, back in the Bundesliga this season, enjoyed a 4-0 win over fourth-division FT Braunschweig.
Eintracht Frankfurt labored to a 2-0 win at fourth-tier side Viktoria Berlin, while second-division city rival FSV Frankfurt defeated fourth-tier Siegen 5-4 on penalties after extra-time finished 3-3.