* Lowry seals victory with a closing 66
* Watson finishes second
* Spieth shoots 66 to tie for 10th (Adds detail, quotes)
By Mark Lamport-Stokes
AKRON, Ohio, Aug 9 (Reuters) - Ireland's Shane Lowry, helped by sensational recovery shots at the 10th and 18th that both led to birdies, clinched his first PGA Tour victory by two strokes at the WGC-Bridgestone Invitational on Sunday.
Two off the pace heading into the final round at Firestone Country Club, Lowry overhauled third-round leaders Jim Furyk and Justin Rose, and held off a charging Bubba Watson with a closing four-under-par 66 in overcast conditions.