Bruno Fernandes struck the only goal of the game for the 1-0 win.
Ten Hag said: "It was clear. Of course we needed that win. We had a tough run of games against good opponents. It wasn't necessary to lose those games. Today was must-win.
"The team spirit and how they fight together [was impressive]. It was a team attacking with 11 and defending with 11. They supported each other.
"A lot has been against us, like injuries and decisions. Like tonight. Murphy's Law where everything goes against us. You have to fight and find a turning point. It shows the dressing room is together. They fight together.
"In stages of the all the games we've played we've played good football but if you want to win you have to do it consistently. That was a brilliant spell of the game. The pass from Evans was brilliant, the movement and finish from Bruno too.
"He [Evans] gave the team calmness. His skills were brilliant, as with the goal."