United have not won in the Premier League since November 10 when they beat leaders Arsenal at Old Trafford but they head to Villa Park on Sunday looking to get their season back on track.
"We are the players and if we lose we have to look to ourselves but I think we did well against Shakhtar," the Dutch left-back said.
"It is hard for everyone when we don't win at home. That is why we fought for every ball and you could see everyone doing that.
"It was good for the team and after recent games to win is good for confidence. It was a very important win.
"We have been a bit unlucky in the league but we have done well in the Champions League and hopefully we can go on a run in the league and beat Villa in the next game."
Buttner was deputising for the injured Patrice Evra against the Ukrainian club but after only 20 minutes of football since the end of October he started to struggle late on and was eventually replaced by Antonio Valencia.
Moyes said Evra's injury was not too serious so the Frenchman may well come back for the Villa game but Buttner is ready to take his chance should the opportunity arise.
"I had cramp in my calf because I've not played for a long time, that was my first game in a month and the last few minutes I was tired," he added.
"I am okay for the weekend. I don't know whether Patrice's injury is bad.
"It is nice to play more games and I hope I can play but I have to wait as it will be the choice of the manager."