Biggar's dead-eye kicking coupled with scores from Tom Smith and Tom Isaacs were enough for the Welshmen to see off a spirited Italian display.
And the 28-year-old Thomas, who has 67 caps for Wales, highlighted Biggar's maturity and coolness under pressure as the key factors behind their successful start to the campaign.
"He's a young player, but he's got an old head on those young shoulders of his," he said.
"I've been at the Ospreys since the start, and from the first day he came in he's been a breath of fresh air.
"As young as he is, he's not afraid to control everybody, and that's what you need from your No. 10. He puts his neck on the line, and he certainly bosses us around.
"Against Treviso he knocked over just about everything that came his way. And that's what you need at this level. He was really excellent."
Forwards coach Jonathan Humphreys echoed Thomas' assessment of the Swansea man who missed out on Wales's World Cup squad with Scarlets' Rhys Priestland preferred.
"Dan was exceptional, given how much of the time he spent on the back foot during a game that we were lucky to still be in at half-time. "
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