Berger three shots clear after superb 62

Berger began the third round, which saw tee times brought forward because of anticipated bad weather, level in a four-way tie for the lead at seven under but went eight under for the day at TPC River Highlands to take command.

The American, seeking his second professional win after victory in the St. Jude Classic in June, made the turn at three under and posted a further five gains on an excellent back nine to move clear of the chasing pack.

Scotland's Russell Knox, South African Tyrone van Aswegen and Russell Henley are Berger's closest challengers at 12 under.

Van Aswegen and Henley had each been part of the tie with Berger at the end of round two and carded just one bogey apiece on Saturday to remain firmly in contention despite Berger stealing the show.

Henley's five-under 65 featured an eagle at the par-five 13th, with his only blemish coming at the third.

Knox, meanwhile, surged his way into tied second with a six-under 64 after birdying on four of his first six holes.

Marc Leishman had been part of the quartet tied for the lead at the midway point but is now nine shots off the pace after a one-over 71, failing to card a single gain on the back nine with two of his three bogeys coming at 10 and 12.

Patrick Rodgers is five strokes back on 10 under, while Bubba Watson and Patrick Reed - both set to represent United States at the Olympic Games - are five under.

Their Olympic team-mate Matt Kuchar is 12 shots back on three under following a disappointing round of 71.