The Welshman, who like Bradley Wiggins made his name on the track, showed his improving climbing ability at last year's Tour when he finished 15th overall after riding mainly to help team leader Chris Froome, who won the overall title for the second time.
In the week-long Paris-Nice race, Thomas beat seven-times Grand Tour winner Alberto Contador (Tinkoff) by four seconds after surviving the Spaniard's onslaught in the final hilly stage, showing great composure and resilience.
He still has a lot to learn to become the third Briton to win the world's greatest race, after Sky team-mates Wiggins in 2012 and Froome in 2013 and 2015.
"One step at a time," said Thomas, who also won the week-long Tour of Algarve last month.
"This year is all about one-week races. I think riding with Froomey, living (on the French Riviera) near him, I learnt a hell of a lot. His record speaks for itself." - Geraint Thomas
Thomas has been following a path similar to Wiggins, starting his career on the track, with both men clinching the team pursuit Olympic title in Beijing in 2008.
He finished his first Tour de France in 2007 in 140th position, out of 141 finishers.
Team Sky, which he joined in 2010, started his transformation into a one-say classic rider. Several coaches and sports directors have lauded his 'huge engine', hinting he had the qualities to become a Grand Tour rider.
The development started last season when Thomas lost considerable weight, at least eight kilos. The all-rounder now believes he could mount a Tour challenge in two years, just before Froome's contract with Sky comes to an end.
"I'm happy where I am at the moment," said the 29-year-old.
"Next year I'm really going to learn what it is about, leading a team. I'm like a sponge, soaking up as much as I can."
"Even if he's attached to the classics, he's been yearning for something else since last year," said Sky sports director Nicolas Portal.
Instead of trying to win Paris-Roubaix, the 'Queen of the Classics' in April, Thomas will be in Tenerife attending a Sky training camp, as the road to the biggest podium of them all draws tauntingly closer.