Abbott was proud of his team, but warned: "The second leg will be even harder than this one because Leeds know they have a lot to do.
"Graham Kavanagh's goal was as good as you will see, but I think the ball hit Joe Anyinsah's head and went in for our second. He's not the best header of a ball but when he came off the bench his pace helped us to get in behind Leeds' defence.
"This is a really tough place to come. The result will give us a lot of confidence which we have to take into our league games.
"Leeds are going through a difficult patch after beating Manchester United, but they have a lot of quality players and will bounce back."