Bruce had a short break in Portugal after the club’s 2-2 draw against Southampton late last month.
Supporters have been critical of the trip on social media, and Bruce was asked about it following this afternoon’s 4-1 defeat to Manchester United at Old Trafford.
United’s head coach said: "Do you think I really have to answer that to you? That's what the fans are asking, are they? We have trained all week, and we were in every day. The preparation was meticulous, let me tell you.
"There is nothing more in preparation (that could have been done). What was I supposed to do? We had six of them away. The preparation was fine, absoutely fine, and we’ve been in all week. You could see the game plan was, what we worked to.
"To have to answer questions like that ... is typical to the question I would get off you – and your newspaper, if I’m being brutally honest. That's why they are the way they are, the way you are and your negativity, constantly, and your newspaper."
Cristiano Ronaldo, making his second Man United debut following his move from Juventus, scored twice, with his first goal coming late in the first half.
"I was very pleased with a lot of it,” said Bruce. “We were a constant threat on the counter-attack.
“We had some really good opportunities. I can’t remember coming here with so many opportunities. The difficulty is giving poor goals away."