O'Leary had no complaints about Paul Fowler's dismissal but was delighted with three points against one of their title rivals.
"It was a good win. Llanelli are a top side with good players but we defended brilliantly, he told the South Wales Evening Post.
"Our two young full-backs and central defenders were dominant and impressive.
"We are in our infancy in our development whereas Llanelli have built their side over a number of seasons, but we have 13 games to go and can still make an impression.
"I was worried that three weeks of inactivity could have affected us but our application was good.
"We knew when we came here that they would put us under pressure but we organised ourselves well."