Hook created Wales's first try with an exquisite dummy
Wales (24) 27
Tries: G Thomas, Wyn Jones, M Jones
Cons: Hook 3
Pen: Hook 2
Argentina (7) 20
Tries: Corleto 2
Cons: Todeschini 2
Pen: Todeschini 2
Wales hung on for a morale-boosting win over Argentina to get their World Cup preparations back on track and relieve the pressure on coach Gareth Jenkins.
After Ignacio Corleto's interception try put the Pumas ahead, Wales hit back through Gareth Thomas's stylish score.
Alun Wyn Jones and Mark Jones put Wales 24-7 up at half-time but Argentina were much improved after the interval.
Federico Todeschini's boot and another Corleto try cut the gap, but Wales held on by the skin of their teeth.
Jenkins has been under intense pressure in the Welsh media since his side's capitulation in the 62-5 thrashing by England two weeks ago.
Wales were eager to make an early statement but that ambition was ended after just five minutes at a sparsely populated Millennium Stadium when Thomas telegraphed his flat pass to Tom Shanklin.
The pass gave Corleto every chance to intercept on halfway and the winger made the most of the opportunity as he showed a clean pair of heels to Hook on his way to the tryline.
Wales had the chance to hit back through Hook's boot, but his long-range penalty struck the post and bounced away for Argentina to clear their lines.
But any Welsh nerves were settled soon after when Hook's textbook dummy took five Argentina defenders out of the equation.
Wyn Jones's impressive performance earned him the man of the match award
The fly-half straightened his line, drew the full-back and handed the supporting Thomas his 39th Wales try on a silver platter.
Heartened by the try, Wales upped the tempo and punished a string of cynical Argentina offences when Wyn Jones went through two tackles to score from Dwayne Peel's quick tap.
Wales' next score came courtesy of a dreadful pass in Welsh territory from the out-of-sorts Agustin Pichot, which Federico Serra knocked-on.
Hook hacked the ball on for Tom Shanklin to take up the chase with two team-mates outside him, and Mark Jones finally dotted the ball down after the chance was almost butchered.
A dreadful challenge on the airborne Wales full-back Kevin Morgan by Argentina winger Lucas Borges was deservedly penalised by a yellow card and Hook's penalty two minutes later put Wales even further ahead.
Argentina offered little in attack, although they did manufacture an overlap only for Serra to inexplicably take an inside line off the ball carrier.
Dominating both possession and territory, Wales ended the half well on top and were unlucky to see Shanklin's scorching break end with the ball bouncing into touch.
Argentina's ragged first-half display was quickly put behind them though as Todeschini's early penalty got their scoreboard ticking again.
A clever kick to the corner from Peel saw Argentina concede another penalty at the subsequent line-out, and Hook had no trouble in converting it to three points.
Argentina were beginning to get their hands on the ball though, and the next score went there way after some dazzling play by their wingers, Borges and Corleto, opened up Wales.
Some delightful handling from a Felipe Contepomi-inspired backline kept the pressure on Wales, and the home side did themselves no favours with a series of missed kicks to touch.
Corleto scored both of his side's tries in Cardiff
With 10 minutes to play, Todeschini stroked the ball over from another penalty to narrow the gap to just seven points.
And Argentina pushed Wales to their limits in the closing stages, with some ferocious forward play keeping Thomas's side pinned in their own 22 and leading to Matthew Rees being sent to the sin-bin.
Replacement Martin Durand looked to have earned his side the chance of a draw in the dying seconds, but the video referee ruled out his effort for a knock-on in the act of scoring, thanks to a heroic tackle from Duncan Jones.
Referee Chris White promptly blew up for full-time to hand Jenkins and his team a much-needed victory ahead of their final World Cup warm-up Test against France next Sunday.
Wales: Morgan; James, Shanklin, G Thomas (capt), M Jones; Hook, Peel; D Jones, Rees, A Jones, Gough, Wyn Jones, J Thomas, Williams, Popham.
Replacements: Rhys Thomas, Jenkins, James, Charvis, Phillips, Sweeney, Robinson.
Argentina: Serra; Borges, Gaitán, F Contepomi, Corleto; Todeschini, Pichot (capt); Roncero, Ledesma, Scelzo, IF Lobbe, Albacete, Leguizamón, JF Lobbe, Longo.
Replacements: Basualdo, Bonorino, Alvarez, Durand, Vergallo, M Contepomi, Agulla.
Referee: Chris White (England).