Coceres, ranked 54th in the world heading into this past week's event at Hilton Head Island, carded a par on the fifth playoff hole on Monday to defeat Billy Mayfair. The 37-year-old Argentinian earned $630,000 and a two-year exemption on the PGA Tour.
Coceres already owns two titles on the European Tour and has won six times in South America.
There were no changes in the top seven, with reigning Masters champion Tiger Woods still holding a big advantage over the second-ranked Phil Mickelson. Ernie Els, Lee Westwood and Colin Montgomerie rounded out the top-five.
Vijay Singh, who posted his sixth top-four finish in nine starts this season with a tie for third at Harbour Town, remained in the sixth position, one ahead of Davis Love III. Singh is currently second on the PGA Tour money list despite the fact he has been unable to find the winner's circle so far this season.
Northern Ireland's Darren Clarke jumped one spot to eighth, while Hal Sutton moved up from 11th to ninth place. Jesper Parnevik of Sweden held on to the 10th position.
David Duval, who is slated to start this week at the Houston Open, dropped three spots to 11th. Duval is coming off his second career runner-up showing at the Masters.
Mike Weir, Jim Furyk and Thomas Bjorn were 12th, 13th and 14th, respectively, while Tom Lehman fell two slots to 15th place. Sergio Garcia, Nick Price, Michael Campbell, Mark Calcavecchia and Padraig Harrington held the final five places in the top-20.
Robert Allenby, the defending champion this week in Houston, lies just outside the top-20 in the 23rd position. Allenby, an Australian, beat Craig Stadler on the fourth playoff hole last year for his maiden PGA Tour win. He went on to outlast Nick Price in extra holes for the 2000 Western Open title, and this year survived a six-man playoff to capture his third victory at the Nissan Open.
Allenby is an amazing 7-0 in playoffs worldwide.
Click here for more golf news!