Aberg birdied four of the last six holes in the Genesis Invitational at Torrey Pines to complete a final round of 66 and finish 12 under par, one shot ahead of American Maverick McNealy.
The 25-year-old Swede who turned pro in June 2023 after an outstanding amateur career won the RSM Classic that year, then finished second three times in 2024, including at the Masters.
The Genesis relocated to Torrey from Riviera because of the devastating wildfires in Los Angeles, and Aberg made good on another chance at one of his favourite courses.
McNealy had set the clubhouse target following a closing 64 but ultimately paid the price for covering the last five holes in one over.
The 29-year-old had to hole from 38 feet to save par on the first, but birdied the next five holes in a row and picked up another shot on the ninth to reach the turn in 30.
Further birdies on the 10th, 11th and 13th briefly gave McNealy a three-shot lead before he dropped his only shot of the day on the 14th after failing to get up and down from a greenside bunker.
Aberg, who had covered the front nine in 34, still need a strong finish to force himself into contention and duly birdied the 13th, 14th and 15th before two-putting from 70 feet for birdie on the par-five 18th.
World No.1 Scottie Scheffler, who shot a 76 on Saturday to fall into a tie for eighth, was 10 shots better on Sunday and finished at nine under, tied for third with third-round leader Patrick Rodgers (71).
Adam Scott (70) finished as the best Australian in a tie for 37th at one over, while compatriots Min Woo Lee (70) and Jason Day (72) were four and six over, respectively.
With Reuters & AAP.
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