* Woods shoots into contention at his own event
* Birdies six of his last 13 holes (Adds detail, quotes)
July 31 (Reuters) - Tiger Woods celebrated a lengthy birdie putt on his penultimate hole with one of his trademark fist pumps on the way to his lowest round of the year in relation to par at the Quicken Loans National in Virginia on Friday.
Woods, who has mainly struggled on the PGA Tour this season while working through his latest swing change as he recovers from back surgery, fired a sparkling five-under 66 in the second round at Robert Trent Jones GC in Gainesville.