Kim Hellberg says "mentality" was the reason behind their dramatic win at West Bromwich Albion.
Boro looked to have squandered two points as Albion fought back from two down to draw level.
But Hellberg's side regained their composure, which allowed a fine move to set up Delano Burgzorg to score a 90th minute winner, a result which kept the Teessiders second in the league.
"The mentality of the players is the key thing here after the crowd goes unbelievably crazy," said the Swede.
"The game was almost done. We were controlling things and they scored a goal from almost nothing.
"They got a lot of energy and have some very good players and then [for us] to come back from that and score a winner in that way [was great].
"It was not a long ball, it was not lucky, it was a top quality goal in the 90th minute and that says everything about this group of lads."
