Saturday’s 46-6 victory for the All Blacks stretched the world champions’ winning run over Wales to 29 games in 63 years, and sent the visitors crashing to their heaviest defeat since 2003.
It was a commanding performance for the All Blacks in Dunedin despite a strong Welsh fight, but the tourists could not compete with New Zealand's tactics in attack, with Ospreys’ Dan Biggar’s two penalties their only scores.
Despite scoring only five tries in the series, and conceding 16, Gatland insists Wales will benefit from their time in the southern hemisphere, with players such as Scarlets’ Liam Williams – who struggled with injury during this year’s Guinness PRO12 – turning in superb shifts in the Land of the Long White Cloud.
"We'll take a lot of lessons from what we've learned," he said. "We need to make sure that we apply that to the next time we're back together.
"It's pretty disappointing. We thought there were a lot of positives out of the first two Tests, but in fairness to the All Blacks I thought they were absolutely outstanding.
"I thought the pace of their back three caused us some problems and some of their collision dominance was pretty good as well."
Wales took an early lead when Dan Biggar converted a sixth-minute penalty, before the Ospreys fly-half landed a second in quick response to Beauden Barrett's first for the All Blacks.
But it didn't take long for New Zealand to find their stride, with Ben Smith putting the ball down just after the 20-minute mark to put Steve Hansen's side ahead, before George Maola and Barrett went over to give the All Blacks a comfortable lead at half time.
Barrett added a second in a 28-point second half haul with Dane Coles and Israel Dagg also touching down with no Welsh response to wrap up the series win for New Zealand.
Follow the Guinness PRO12 on Facebook, join the conversation on Twitter, sign up to our YouTube channel for extensive match highlights and sign up for our newsletter for regular updates on the Guinness PRO12.