Manchester United manager Louis van Gaal has said that the Red Devils are in a "rat race" to qualify for the top four.
The top seven sides in the Premier League all won their midweek fixtures, with the gap between fourth and seventh being just six points.
"I said in the dressing room that I was very pleased with the performance. This is a difficult ground to win. We dominated the game," the 63-year-old told reporters.
"When you don't do that, you can end up with a negative result. It could have been because David de Gea made two fantastic saves. But, I have to say, Tim Krul did also.
"We have waited a long time for the winning goal but it shows the fighting spirit of our team again. I have said that a lot. For me, it was very important to win. All our competitors in our rat race [for the top four] have won too."
United remain a point behind third-placed Arsenal, who beat Queens Park Rangers 2-1 on Tuesday night.