A Bruno Fernandes spotkick was the difference between the two teams.
"We have a tradition of making it hard for ourselves," he said, as United finally ground out a league win at home this season. "When I was a player here Sir Alex [Ferguson] used to say that 'that's why I'm going to have heart trouble', but he's still healthy so that's fine.
"Towards the end we seemed edgy, because we could have seen the game off with a couple of good chances.
"Delighted with a clean sheet but we could have made it more comfortable. International breaks, they never help. All our prep was this morning, so it's not easy when you only have 20 minutes or half an hour to prepare for a game.
"Three points, home win, so we can stop talking about. But if we want to move up the table, we have to play better."