Juan Cruz Mallia, center, celebrates with the teammate Santiago Gonzalez Iglesias after scoring a try during against the Sunwolves. Photo: Gustavo Garello/AP Photo

BUENOS AIRES The Argentine Jaguares sealed second place in the Super Rugby standings by trouncing the Japanese Sunwolves 52-10  on Friday in Buenos Aires despite fielding a virtual reserve team.

Already guaranteed a home quarter-final next weekend, the South Americans' reward for being runners-up behind the Crusaders will be a home semi-final as well if they qualify.

It was the ninth victory in 10 matches for the South American outfit after they lost four of their first six matches this season.

The home side scored eight tries and the match was effectively won and lost in the final minute of the opening half and the first of the second half.

Trailing only 14-10 as the interval approached, the Tokyo-based visitors conceded a penalty try for an infringement that resulted in star full-back Semisi Masirewa being sin-binned.

Reduced to 14 men, the Sunwolves fell 26-10 behind less than a minute into the second half when Julian Montoya surged over the line at the conclusion of an unstoppable rolling maul.

From then on the issue was not who would win but by how much with the Jaguares growing increasingly strong against opponents resigned to their fate.

The Jaguares will only know Saturday which team they face at the last-eight stage after the final regular season matches are played in South Africa.

Defending champions the Crusaders, fellow New Zealand side the Wellington Hurricanes and the ACT Brumbies from Australia are also going to host quarter-finals.

But who they face depends on the final placings with the Northern Bulls of South Africa and the Waikato Chiefs of New Zealand sure to be among the travelling teams.

The other two places rest between South African sides the Western Stormers, Coastal Sharks and Golden Lions and the Otago Highlanders from New Zealand.

Making 12 changes to the team that comfortably defeated the Sharks in Buenos Aires last weekend, the Jaguares led after 11 minutes and were 21-10 in front by half-time.

It was one-way traffic toward the Sunwolves' tryline in the second half with the Argentines adding five tries while the visitors failed to score.

Argentine lock Guido Petti stretched sporting diplomacy to its limits later when he said the Sunwolves were "very tough opponents.

"It was a great game which we managed well and the team never relaxed in pursuit of scoring as many points as possible.

"Although we were already assured of a home quarter-final, we approached this game determined to win so that we can stay in Buenos Aires for the semi-finals if successful next weekend."

New Zealand-born Sunwolves flanker and skipper Dan Pryor said he was "very disappointed with the result but proud that the team never gave up.

"Poor discipline has been a major problem for us all season -- we concede way too many penalties."

Sebastian Cancelliere (two), Santiago Carreras, Montoya, Juan Cruz Mallia, Matias Moroni and Javier Ortega Desio scored tries for the Jaguares, who were also awarded a penalty try.

Domingo Miotti succeeded with five of his seven conversion attempts.

South African Gerhard van den Heever and Fijian Masirewa scored a try each for the Sunwolves, but usually accurate New Zealander Hayden Parker fluffed both conversion kicks.