Mourinho, who made nine changes to the side that won against Burnley on Monday , has admitted his side were lethargic at Bosuilstadion.
Spurs’ fringe players failed to impress as Lior Refaelov’s first half goal was enough to hand Ivan Leko’s men their sixth consecutive victory in all competitions.
Mourinho was left fuming at Tottenham’s display after the game but was quick to praise Antwerp for playing very well.
"We can only blame ourselves and we can only praise the opponents. I prefer to praise the opponents because they played a magnificent game and not to blame ourselves because we played an awful game,” the former Manchester United and Chelsea coach told the club’s official website.
"But I have to do both at the same time. Praise them because they were playing at the maximum of their level and we have to blame ourselves because we were poor.
"The performance was poor and the result is poor. Somebody to blame? Blame me because I am the boss and it is my responsibility who plays and I am the one to blame.
"But I have to admit that the game confirmed to me a few things, opened other question marks and will help me in the future with my decisions. I'm also learning every day."
Next up for Tottenham and Mourinho is a home Premier League game against Brighton and Hove Albion on Sunday.
