Federico Todeschini and Miguel Avramovic scored second-half tries as Argentina fought back from a six point interval deficit to beat Italy 23-16 on Saturday.
Todeschini's kicking contributed another 13 points as the Pumas followed up last week's stunning 25-18 win over world champions England with a solid rather than spectacular display at the Flaminio stadium.
Marko Stanojevic scored Italy's only try a minute from time after David Bortolussi's boot had yielded 11 points for the Azzurri.
The match was billed as a derby with six of Italy's starting XV born in Argentina and nine of Argentina's line-up of Italian origin.
The ties between the two countries date back to shortly after World War I when thousands of Italians emigrated to Argentina to find regular work.
With one eye on the final match of their European tour against France next week, Argentina coach Marcelo Loffreda made eight changes to his side which won at Twickenham.
Argentina should have scored a try in the third minute, but front-rower Marcos Ayerza suffered a lapse of concentration and let the ball slip through his fingers when clean through in Italy's 22.
The visitors plugged away and Todeschini's penalty opened the scoring in the 15th minute, only for Bortolussi to quickly restore parity after some Argentine indiscipline.
Bortolussi skewed an easy penalty on the half hour, but soon made amends with a huge kick from the halfway line.
Italy extended their advantage on the stroke of half time when Longo came in late on Ramiro Pez, Bortolussi comfortably slotting between the posts for a 9-3 half-time lead.
Todeschini reduced the arrears to three points five minutes after the restart before scoring the game's first try.
Ignacio Corleto broke down the right wing and eluded a poorly-timed tackle by Italy captain Marco Bortolami before teeing up Todeschini for an easy score.
Avramovic pulled Argentina further head, linking up superbly with Martin Durand before touching down.
Stanojevic went over in the 89th minute as Italy made a late surge before Todeschini's coolly-struck penalty wrapped up victory.
While the Pumas visit France next week, Italy conclude their November tests at home to Canada.
