Apia - A two-try effort from Steffan Evans gave Wales a narrow 19-17 win over Samoa in Apia on Friday on a quagmire pitch.
The Scarlets wing ensured Robin McBryde's men had back-to-back victories after last week's win over Tonga, with the 22-year-old crossing for the game's deciding try in the 74th minute.
The young Wales side - missing 16 front-line players and coach Warren Gatland to British and Irish Lions duties - gave it their all in draining conditions.
They were facing a physical Samoa side determined to impress on home soil after being thrashed 78-0 by the All Blacks in Auckland last week.
"It's one of the toughest games I've played in, the conditions were pretty atrocious and both teams were limited to playing a bit of a kicking game," Wales captain Jamie Roberts said.
Heading into the match, Roberts was on 95 caps, 33 more than the rest of the starting XV combined.
"I'm so proud of the lads," he said. "It was a bit of an arm-wrestle but to come through in the last 10 minutes showed a lot of grit from the new lads."
Wales hit early trouble when Samoa spread the ball wide after a scrum, then sent a long-distance pass to an unmarked Alapati Leiua to score on the other wing. Tusi Pisi added the conversion and a penalty to make it 10-0 as Wales struggled in humid, rainy conditions.
The Samoans, who lost 78-0 to the All Blacks last week, gave Wales no space and forced four turnovers in the first 10 minutes with ferocious tackling before the tourists steadied.
Fullback Gareth Anscombe almost had a try after showing impressive soccer skills kicking the ball through the Samoa defence, but it was three penalties from flyhalf Sam Davies that narrowed the score to 10-9 at the break.
A Davies mistake was nearly costly when he tried to kick the ball out on the half-time siren, but failed to find touch and Samoa threatened to score.
The tourists took the lead immediately after the restart when Evans crossed after Josh Navidi charged down the ball to give them possession.
Samoa hit back when Kahn Fotuali'i caught the Wales defence napping, setting up a converted try for Manu Leiataua.
Errors mounted as players tired on the muddy field but Wales patiently
worked the ball up the middle for 12 phases before shifting it wide for
Evans to dot down his second in the corner.
It gave Wales a two-point lead with five minutes on the clock and Samoa threw everything into attack but could not find a way through the desperate defence.
Tries: Alapati Leiua, Manu Leiataua Conversions: Tusi Pisi (2)
Tries: Steffan Evans (2)
Penalties: Sam Davies (3)
15 D’Angelo Leuila, 14 Alapati Leiua, 13 Kieron Fonotia, 12 Rey Lee-Lo, 11 David Lemi (captain), 10 Tusi Pisi, 9 Kahn Fotuali'i, 8 Fata Alafoti Faosiliva, 7 Galu Taufale, 6 Piula Faasalele, 5 Faatiga Lemalu, 4 Chris Vui, 3 Paul Alo-Emile, 2 Maatulimanu Leiataua, 1 Viliamu Afatia
Substitutes: 16 Seilala Lam, 17 Nephi Leatigaga, 18 Bronson Fotualii-Tauakipulu, 19 Faifili Levave, 20 Vavae Tuilagi, 21 Dwayne Polataivao, 22 Henry Taefu, 23 Tila Mealoi
15 Gareth Anscombe, 14 Cory Allen, 13 Tyler Morgan, 12 Jamie Roberts (captain), 11 Steffan Evans, 10 Sam Davies, 9 Aled Davies, 8 Josh Navidi, 7 Ellis Jenkins, 6 Aaron Shingler, 5 Rory Thornton, 4 Seb Davies, 3 Dillon Lewis, 2 Ryan Elias, 1 Nicky Smith
Substitutes: 16 Scott Baldwin, 17 Wyn Jones, 18 Rhodri Jones, 19 Adam Beard, 20 Thomas Young, 21 Tomos Williams, 22 Owen Williams, 23 Scott Williams