Jose Mourinho would not divulge where he watched Manchester United's 4-1 win over West Ham in the EFL Cup quarter-finals.
Mourinho was not seen inside Old Trafford after accepting a touchline ban earlier in the day for his dismissal during Sunday's Premier League clash between the same two sides.
Asked by Sky Sports 1 where he chose to watch the tie, Mourinho answered: "It's a secret. I was in contact with the bench.
"Yesterday we worked really well and everybody was prepared. At half-time I could be face to face with the players and on top of that I trust my assistants to pass on the information we need.
"I'm really happy with the players."
Anthony Martial booked his side's place in the last four with two goals early in the second half after former United player Anthony Fletcher had cancelled out Zlatan Ibrahimovic's early opener.
Ibrahimovic added gloss to the scoreline with his second of the night in stoppage time.
Henrikh Mkhitaryan produced another impressive performance in the Manchester United midfield to earn the praise of his manager.
"I'm so happy with his performance today because it was against a Premier League team with Premier League qualities and characteristics," said Mourinho.
"Against Feyenoord we could think, 'Okay, it's a different profile of football but today against a typical Premier League team, 'Micky' could perform this way.
"We are really happy. We know the reason we bought him and were waiting for his reputation. It looks like it's coming."
Mkhitaryan, who was named man of the match, said: "I'm pleased that we won. It was a very important game because now we're in the semi-finals.
"We've done a good job and need to keep going.
"Playing in a cup final at Wembley is a dream but it's not the main goal now. We have to focus on the next game and we'll see what happens."
United will face Hull in the semi-finals with rivals Liverpool drawn against Southampton.