Boffelli scored a superb try and kicked six penalties and Santiago Carreras also crossed as the Pumas went toe to toe with the favourites on a horrible wet day to give them a huge boost ahead of next September's Marseille clash.
"We said at halftime that we must stay close in the score, then we got two tries," Boffelli said. "Our attitude was important. To score 25 points at Twickenham is great. The whole team did their job."
England's much-heralded combination of Marcus Smith, Owen Farrell and Manu Tuilagi barely featured and the home side committed far too many errors and can have no complaint about the result.
"We talked about some issues we had on the field that we didn't address, we can't drop confidence because of this," Farrell said.
"We had scrappy parts of the game which will get better, the discipline is avoidable and it wasn't quite happening. We let the pressure off at times. It was a wet day, a wet pitch and as you saw both teams didn't move the ball well.
"The penalties stopped our momentum. We weren't at our best and that's what we are here to do."
HANDLING ERRORS
England, who led 16-12 at half time, scored through Joe Cokanasiga and Jack van Poortvliet but showed precious little attacking invention and kept the visitors in the game with a succession of penalty offences and handling errors.
After a cagey opening quarter England eventually struck off a scrum in the 26th minute as recalled winger Cokanasiga powered his burly frame over from close range to take his international try tally to 12 in 13 appearances
Argentina had not done much with the ball but stayed in touch via four Boffelli penalties and with Farrell landing three, England, wearing their new black strip, edged the largely forgettable half.
The Pumas cut loose seven minutes after the break as they fizzed the ball across the backline to allow Boffelli to slide in at the corner.
Five minutes later they scored a second when Carreras seized on a loose ball to run 50 metres and score. Farrell claimed his misplaced pass had been knocked on but the TMO view ruled otherwise.
England had to hit back quickly and did so through Van Poortvliet, who showed great pace and determination a minute after coming on to replace Ben Youngs at scrumhalf. Farrell converted to make it a one point game going into the final 20 minutes.
Twickenham sat back for an expected home surge, but though they briefly got their noses in front, England failed to take command as two penalties apiece kept Argentina ahead and they controlled the final five minutes superbly to claim the win.
England face Japan next Saturday - also World Cup pool opponents next year - before playing New Zealand and South Africa, all at Twickenham.
Argentina next face Wales and Scotland.
Check out the match summary for all the details on Argentina's famous win.
