Pochettino said: "I am frustrated, the same as the rest of the boys, because the team played a great match. The effort that the team put in, they deserved the victory today. It could be two victories and one draw.
"That's football. Sometimes you have luck and sometimes you don't have luck. But you have to work to produce your own luck.
"At Old Trafford we had two very different halves, raising our game a lot in the second half. I think in the last 10 minutes of the first half today we started to play the same way that we did all through the second half on Wednesday."