Thirimanne came into Sri Lanka's side for the Third Test against Australia at the SCG after the injury to Kumar Sangakkara, and immediately looked at home making an outstanding 91 in the first innings.
He was then run out without facing a ball in the first one-day game at the MCG on Friday as Sri Lanka lost by 107 runs, but he was part of a much better showing in Adelaide on Sunday.
He brought up his maiden international century to finish up 102 not out as Sri Lanka cruised to 2-172 in 40.1 overs chasing down Australia's 170.
The 23-year-old was playing his 33rd one-day match for Sri Lanka having also played eights Tests and 11 Twenty20 internationals, but after getting so close to a century in the Test in Sydney, he was nervous as the milestone approached.
But once he got there and when he was able to help Sri Lanka home to victory, he couldn’t have asked for anything better.
"In the Sydney Test I thought after the match that I could have got the century, so that was in my mind when I was in the 90s again tonight. I just tried to keep my head still and play along the ground, and Kusal (Perera) helped me a lot to stay calm and make sure I scored the hundred," Thirimanne said.
"It's my maiden hundred and I'm really happy about it especially to score it in Australia. Early on we just wanted to keep wickets intact so myself and Dilshan did that really well.
"It was a great performance by (Tillakaratne) Dilshan, he batted really well and we talked about how we wanted to bat through the innings. We knew we were chasing a low score and only had to score 170 so we wanted to bat through the innings, and almost did that."
Sri Lanka was understandably disappointed with their tour to date having lost all three Tests and the first ODI, so while the toss was a good one to win to bowl first in Adelaide, Thirimanne thinks the turnaround was more because every member of the team took the responsibility to stand up.
"I think it was a good toss to win and we always thought batting second was a good option. Early on the ball didn’t come onto the bat so well so I think it was a good move by Mahela for us to bowl first," Thirimanne said.
"Our team's confidence is really high at the moment. After the Melbourne match we spoke about the areas we wanted to improve in and I think we did really well in this match. Our bowlers did their jobs and the batters did their job, so it was a great team effort."