The 20-year-old Finn, who scored a season-opening fifth place in the Principality last season on his Toyota Gazoo Racing debut, halved the gap to the winner this time around.
He led for one stage on Friday and was only ruled out of a podium fight with Thierry Neuville by a flat tyre on the first stage on Sunday morning.
“I think there’s been a big improvement from last year. I didn’t have so much driving on Tarmac last year – the only event I have done on this surface since Monte last season was Monza at the end of the year,” said the Yaris pilot.
“I feel like this time I was fighting on a very good pace. It felt like I was really chasing the podium properly. I’m happy for that and that makes it a good weekend. The conditions were not so easy, but we managed to keep some consistent pace which was a lot faster than last year.”
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Talking about the last-day tyre issue which dropped him from third to fourth, he added: “I think it was bad luck. I couldn’t see anything and on the second time through that stage, I was looking again to see what caused it but I could see nothing.
“It was unlucky, but that’s how it goes. Now we look forward to Arctic [Rally Finland] and a surface I am more at home with.”