With the Reds already through to the Champions League knockout stages, Wednesday's result was inconsequential for a United side sprinkled with youth and players only recently returned from injury.
"We achieved what we wanted to achieve, without getting the result," the manager said. "We gave players game time and brought young players back in. The more game time Chris Smalling and Phil Jones get can only help us.
"I thought Phil was outstanding tonight. Getting him and Chris back is a big plus-point.
"I think all our defenders did their job pretty well. Scott Wootton's only had a few games with the first-team, Jones and Smalling have been out a long time and Büttner's only played three games for us. Considering that, I was pleased with their composure."
Despite dominating the match and producing 23 attempts at goal, United lost to a Luis Alberto strike Sir Alex described as "a wonder-hit".
"It's a fantastic goal they scored to beat us," he said. "He bent it away from David [De Gea], who had no chance with it. It was just one of those nights. We didn't take our chances.
"It was cold and the ground became a bit dead so the ball didn't run as fast as normal. But we still could have won the match and I think the best football came from us."
Sir Alex was talking to reporters at his post-match press conference and to MUTV.