The Australians outscored the error-prone Argentines by six tries to two at Estadio Jose Amalfitani to secure a bonus point and a nine-point lead over the Waratahs in the Australian conference.
A clinical victory in South America completed a tour that yielded nine points from a possible 10, after a 19-10 win over Southern Kings in
Brumbies and arch-rivals Waratahs have three fixtures left, and the odds are stacked in favour of the
Banks scored the victory-clinching try against the Kings and struck twice midway through the first half in
He ran a brilliant line, took a pass from scrumhalf Joe Powell and darted over on 25 minutes for his first try.
Almost immediately after, Jaguares wing Bautista Ezcurra failed to hold a high ball, and when Brumbies flank Chris Alcock kicked to the corner, Banks was there to score spectacularly.
Flyhalf Wharenui Hawera kicked a penalty before halftime for a 20-10 advantage over opponents reduced to 14 men when skipper and hooker Agustin Creevy was yellow-carded for a cynical foul.
It was not what Jaguares supporters had expected after a promising start in a stadium also used by a leading football club.
Flyhalf Nicolas Sanchez slotted a penalty and, after skipper and lock Sam Carter claimed a pushover try converted by Hawera, Argentine lock Tomas Lavanini bulldozed across the line.
With star Sanchez receiving treatment for a cut, temporary replacement Santiago Gonzalez Iglesias kicked the conversion for a lead they held until Banks turned tormentor.
Any hopes Jaguares had of staging a dramatic second-half comeback faded on 56 minutes as relentless pressure culminated in wing Henry Speight scoring a fourth Brumbies try.
Substitute Andrew Muirhead added two more in the final 10 minutes, both of which Hawera converted to compensate for three earlier missed shots at goal.
All Jaguares could manage was a pushover try by replacement lock Guido Petti two minutes from time.
While a revitalised Brumbies outfit can return home confident of more success when they host Melbourne Rebels next weekend, the outlook for Jaguares is bleak.
After getting off to a great start with four wins in five matches, they have lost six of the last seven, including three in
The drubbing by Brumbies was the second heaviest in