The 27-year-old Ulsterman finished with a 26-point haul, consisting of one try, three penalties and six conversions, in a display which coupled superb kicking with moments of attacking brilliance.
O'Driscoll said: "It was a very complete performance from Paddy. It's always difficult to start your first international at fly-half, no matter who the opposition are.
"Sometimes it's easier to play against a more structured side than the Pacific Islanders because you have a better idea of what they will do.
"At times the Pacific Islanders don't know what they're going to do themselves so Paddy responded well in difficult circumstances.
"He made some half breaks, took the ball into contact and was involved as much as possible. I'm sure he'll be very pleased with himself. Eddie will be pleased too."
Ireland have been looking for back-up to O'Gara since Ulster's David Humphreys announced his international retirement.
Humphreys may yet be tempted back into the Test arena for the World Cup, but even if he does go to France next year a few more performances such as Sunday's mean room will be made in the squad for Wallace.
He pulled the strings with a calm authority which belied his lack of Test experience - yesterday was his second cap - and he revealed how early touches calmed the nerves.
Wallace said: "I was happy with just about all aspects of my game and was pleased to finish with 26 points. It was great to be involved at the Lansdowne Road send-off.
"My try came following nice work from Peter Stringer and I just got on to the end of a good pass from him.
"I got my hands on the ball early which was what I was hoping for given it was my first full start.
"Getting comfortable early was a big thing. I wasn't as nervous as I thought I'd be but that was because I got my hands on the ball early.
"It was a job well done. The whole series has gone well for Ireland."
Simon Easterby ran in two tries while Wallace, Denis Hickie, Malcolm O'Kelly, Shane Horgan, Rory Best and Paul O'Connell also crossed, with Ireland doing the telling damage in first-half injury-time.
Seru Rabeni, Lome Fa'atau and Tusi Pisi crossed for the Islanders who had pegged Ireland back to 16-12 before falling away.
O'Driscoll said: "There were wholesale changes for this game and that makes a difference to continuity.
"At times we played some fantastic stuff and at times it was a little bit loose, namely after our first try. We didn't play the direct football we needed to.
"The way we closed out the first half was very pleasing. In the second half we waited for opportunities to arrive rather than forcing them.
"Sometimes rugby is a patience game and you have to wait to score your tries. We're learning that."