* Watson fires a 65 for four-way tie at top * Spieth cards 74 in 'worst round I've played in years' (Updates at end of round) EDISON, New Jersey, Aug 27 (Reuters) - Bubba Watson charged into a tie for the first-round lead at The Barclays on Thursday while newly crowned world number one Jordan Spieth struggled to his worst score of the year in relation to par. Twice Masters champion Watson used a red-hot outward nine as a springboard en route to a sizzling five-under-par 65 at Plainfield Country Club, setting the pace with fellow Americans Spencer Levin and Tony Finau, and Colombia's Camilo Villegas. New Zealander Danny Lee, Americans Jason Dufner, Cameron Tringale and Bryce Molder, and Britons Paul Casey and Russell Knox opened with 66s in the first of the PGA Tour's four lucrative FedExCup playoff events. More...