Louis van Gaal criticized new signing Bastian Schweinsteiger and his Manchester United team mates after the Premier League giants eased to a 3-1 victory over the San Jose Earthquakes.
United recorded a second straight victory on their US tour and never really looked troubled against their mid-table opponents from Major League Soccer.
Juan Mata and man-of-the-match Memphis Depay scored first half goals for United before Brazilian youngster Andreas Pereira added a third in the second half.
But United boss van Gaal was furious at the performance of his team after the break when he made 10 changes, including the introduction of Schweinsteiger.
"The first half I was satisfied -- the players have performed what we wanted in the defensive organization, and they have created a lot of chances, 10, and they scored two goals so I was satisfied," van Gaal said.
"But the second half I thought we played very bad -- a lot of ball losses, very unnecessary. The only highlight was the goal from Pereira.
"We didn`t give many chances away but we gave possibilities away.
"It was a threat always and that was not necessary.
"Our positions in midfield were not so good as in the first half."
Asked to assess the performance of new signing Schweinsteiger, van Gaal didn`t mince his words.
"He was also bad," the Dutchman said, warning it would take time for the German World Cup-winner to settle in at United after arriving from Bayern Munich.
"Players can play bad, certainly when you have only three days or six days training session in your legs and you have to play 45 minutes.
"Everybody can think it is easy to step in but it is not easy. I thought the first match (Schweinsteiger) played very well and now he played bad but that is also a process."
Van Gaal however would have drawn encouragement from the display of Depay, who completed a $38.9 million move to Old Trafford in June.
With former United boss Alex Ferguson amongst an 18,000-capacity sell-out at San Jose`s Avaya Stadium, United eased into their attacking stride quickly.
They created a promising opening after only four minutes when Depay broke forward menacingly before whipping in a low shot which was parried clear by San Jose goalkeeper David Bingham.
Four minutes later, United threatened again when Luke Shaw powered down the left flank and crossed for Wayne Rooney who was just unable to make contact.
United finally broke through on 32 minutes. Ashley Young fed Mata who cut into the penalty area and chipped across goal to beat Bingham off the far post.
Five minutes later United were 2-0 up when Depay, by far the sharpest of United`s attackers on display, pounced on a poor back pass by Jean Baptist Pierazzi to coolly tuck away his finish.
But a largely trouble-free opening 45 minutes was blotted shortly before half-time as San Jose pulled a goal back through Fatai Alashe.
Shea Salinas embarrassed Morgan Schneiderlin down the right flank, feinting past the midfielder far too easily before picking out Alashe with a low cross to finish past United goalkeeper Sam Johnstone.
The mass of substitutions at half-time disrupted United`s rhythm but they were soon back in the goalscoring groove with Pereira making at 3-1 on 61 minutes.
England Under-21 international Jesse Lingard chipped in a pinpoint cross from the right flank and Brazilian youngster Pereira lost his marker to steer home past Bingham.
United will play European champions Barcelona in their match of the International Champions Cup exhibition tournament on Saturday at Levi`s Stadium in Santa Clara, home of the San Francisco 49ers.