Red Devils boss also reserved special praise for Michael Carrick after an impressive performance in the middle of the park, a position that has raised questions recently
Ferguson and his men traveled to the Liberty Stadium to face a Swansea side yet to lose at home this season, but left with all three points and a clean sheet thanks to Javier Hernandez’ 11th minute goal.
Sir Alex paid homage to his players, insisting they worked hard for their victory against a good team, while he also praised his defence following intense criticism before the international break, believing their concentration to be perfect.
"They [Swansea] have a great home record so that was obviously something we thought about before the game and it meant we had to make sure we defended well," the 69-year-old Scot said to ESPN after the match. "Apart from that miss they had in the first half where Michael Carrick miskicked his clearance, other than that, I thought we were comfortable defensively, but they are a good football team and they move the ball well so you are having to concentrate all the time."
United's defense had previously come under criticism for its lack of concentration after a 6-1 drubbing by city rival Manchester City, but has now kept a clean sheet in each of its last five games in all competitions.
"The concentration today is exactly the concentration we need because a few weeks ago there was a genuine criticism of the defending and the chances opponents were getting," Ferguson said. "Swansea didn’t really make any chances apart from when Carrick slipped and apart from that, we were comfortable and had good possession of the ball."
Ferguson also pointed out room for improvement, namely in taking its chances.
"Maybe we should have done better with the chances we did get on the counter-attack, like just before half-time when Chicharito tried to square it for Wayne [Rooney] and near the end we could have had a couple, but in the context of the way Swansea have been going, it was a good result," he added.
Saturday’s shutout marked United’s sixth clean sheet of the Premier League season, more than any other team so far, and Ferguson was quick to point to the importance of a solid defense before heaping praise on one of his midfielders.
"I think for some us this has been a wake-up call," he said. "Over the years it has been an integral part of our success when we defend like that and when the whole team did that. Michael Carrick today for instance was magnificent; it was a big performance from Michael."
Ferguson also hailed his players returning from injury as key, with second half substitutions reviving a flagging United side.
"It was good to get those [injured] players back because towards the latter part of the second half I felt we needed a couple of changes," he added. "The substitutes we did make really made an impact on the team. Darren Fletcher did really well, Antonio Valencia did really well. That squad I’ve got now is a strong squad and I can make changes with confidence and that is very important at this time of year."