Golf:Jason Day underlined his status as one of golf's bright young things with a sparkling round of 63 when the WGC-Bridgestone Invitational began today. At seven under, the Australian leads by three on a morning when Graeme McDowell enjoyed contrasting fortunes.

McDowell out-scored McIlroy by four over Firestone’s back nine to reach three under but things went awry after the turn as he ran up a bogey six on the long second.

McIlroy had endured a slow start, turning on one over, but there was an amazing six-shot swing between the two on the second and third holes.

McDowell followed his bogey with a double-bogey six after driving into rough this time and laying up short of the water, while McIlroy hit a brilliant 230-yard approach to within six feet of the flag to set up an eagle and then birdied the next.

He was up to joint 10th with Donald, but McDowell was all the way down to on one over after dropping another shot on the fourth when he came up short in another bunker. He did hole another birdie at the seventh but dropped another shot at the last to complete a frustrating day.

All of this, of course, was seen as something of a prelude before the return to action of seven-time winner Tiger Woods, out with knee and Achilles tendon injuries since mid-May. Paired with new British Open champion Darren Clarke, he was among the later starters.