Declan Kidney's men now turn their attentions to Sunday's home tie with England as they look to push on towards a repeat of their 2009 Grand Slam triumph.
"This Championship's about momentum. If you lose the first you're in trouble, if you win you're in a good spot. We have to build on this," said O'Driscoll.
"The understanding from winning the Grand Slam in 2009 is that even when you're not great, you have to be good. Consistency will be the key for this Six Nations.
"It was a very physical game, real Six Nations stuff which you expect when you come to Cardiff. We'd lost the last three to Wales and we just felt as though we needed to stop the rot.
"It's a good start for us in this Six Nations. It puts us in a good place with England to come next week. "
O'Driscoll was written off by critics after he was forced to miss most of last season with a shoulder and neck injury but the 34-year-old has hit back in style since then.
The 2005 Lions skipper, who also toured with Britain and Ireland's elite in 2001 and 2009, now appears on course for a fourth successive adventure after he scored his side's third try on Saturday and set up Simon Zebo for the first despite only having recently returned from an ankle injury.
"The big thing is trying to be fit and getting as close to 100% fit as you possibly can when you take to the pitch," added O'Driscoll.
"It felt good - the ankles both felt good, and all the other bumps and bruises felt good, so if you can start games that way, you've every chance of putting in a half decent performance.
"A few things ran for me and I managed to get across the tryline but it doesn't matter for anything if we didn't win the game.
"We won that and I'm delighted, like everyone else is."