Goals from Jed Wallace and George Saville set the Lions on their way to victory, and despite Stewart Downing pulling one back for Boro, it was Millwall who took all three points.
Monk was particularly frustrated at the way his side failed to cope with Millwall’s direct approach, having warned his players of what to expect before the game. He said:
“At the risk of repeating myself, it’s just naive, it’s extremely naive. We know coming here, we’ve prepared the players all week, the direct play it’s going to be. That battle, that physical element to it, in terms of competing for those second balls, very direct stuff.
“To then be so naive and lose a lot of those battles in that first half in important areas and again in leading to the goals, it’s naive, schoolboy stuff. I’ve said it too many times this season.
“It’s never through a lack of effort within the group. It’s just comes back to naivety. I feel like a broken record at the moment. Schoolboy errors, so avoidable and basic stuff.
“And you don’t expect that from the level of players we’ve got, but unfortunately it’s happening too many times this season, but we have no other choice but to work and try and come through it.”
“Top teams don’t particularly like coming here this season. We are what we are as a football club. We have to make it hostile, intimidating. We have to play aggressive football with and without the ball. We play very good football as well, you see that with the first goal in particular.
“We haven’t got players that are worth millions of pounds, but I think I’ve got a lot of players growing in reputation at this level because they are very good footballers.
“The biggest credit I can give them is they are a very good team, as in together. I thought we made a top Middlesbrough side look really ordinary today at times.
“The only disappointment is that we didn’t keep a clean sheet and we didn’t go and score four or five.
“When the game became rough and tumble and aggressive and a fight, we shone and we dominated.”