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.