Connor Ronan’s wonderful second-half finish handed the Buddies the win which has the team just outside the top six.
Goodwin revealed a period of reflection during the winter break prompted a change to the side’s formation, switching from a back three to a back four.
"What pleased me was the discipline the team showed believing in the system and instructions we've given them,” the St Mirren boss said.
“We worked hard on a different formation during the break and it gave me the chance to analyse the first half of the season.
“Things weren't going to plan with the back three so we changed things a bit and we're seeing the benefit.
“The back lads will get the praise for the clean sheet but we defended well from the front.”
Goodwin reckons Jamie McGrath “showed the fans” his commitment to St Mirren after returning to the team after being left out for the last two matches due to transfer uncertainty.
He also believes the midfielder is an excellent example for Ronan.
“It was another quality goal and I think he can go again,” he said.
"He's not the finished article – there's still room for improvement.
“Jamie McGrath has had that international recognition and Connor is capable of doing the same. “The FAI are well aware of the quality he has and he just needs to keep doing that.
“If he continues with performances and goals like that – it'll be shown over social media and on TV – and no doubt Stephen Kenny will see it.”
With just a week of the transfer window remaining, Goodwin revealed the club are on the lookout for further additions.
“We've identified a couple of very good players,” he said. “I have a very good relationship with my board and we all want to strengthen but I'm realistic to know there is no open cheque book.
“Two or three players have been told they're free to go and move somewhere else. If that happens it'll hopefully allow me to add some quality.”