Gilmour (with Ainslie) is red hot
Both skippers are undefeated, with six wins on the board, after a long tough day on the water.
Gilmour is defending the trophy he won last year, and has bought out the big guns, with Olympic gold and silver medallist Ben Ainslie in his crew.
Magnus Holmberg is the current leader of the Swedish Match Grand Prix Sailing Tour, as the second year of the Tour goes past the half way stage.
Hanging in close behind these two is American skipper Ken Read, sailing for Dennis Conner's Stars & Stripes Cup campaign representing the New York Yacht Club.
This is a particularly impressive performance from Read, who is competing in his first grand prix match racing event.
Explaining his success, he praised his tactician: "Terry Hutchinson is awesome at seeing the water, so we feel like in shifty conditions that we have a strength," he said. "When ever you're confident you sail better, and when you sail well, you win," he added.
Sharing fourth place are two non-Cup skippers, Frenchman Luc Pillot, and Denmark's Jes Gram-Hansen, both with three wins and three losses.
The competition on the water has been fearsome, and it is an indication of the depth of talent in this field, that big names like Chris Dickson and Gavin Brady are on the bottom half of the ladder.
The day started out with a strong southeasterly breeze, which was eventually overcome by the legendary Fremantle Doctor seabreeze.
The Sun Microsystems Australia Cup runs from Wednesday 21st March to Sunday 25th March, with twelve top international crews competing on the Swan River's Matilda Bay.
Scores after day 1:
Magnus Holmberg (SWE) 6 - 0
Peter Gilmour (USA) 6 - 0
Ken Read (USA) 5 - 1
Luc Pillot (FRA) 3 - 3
Jes-Gram Hansen (DEN) 3 - 3
Andy Beadsworth (GBR) 2 - 3
Nicola Celon (ITA) 2 - 4
Chris Dickson (USA) 1 - 4
Neville Wittey (AUS) 1 - 3
James Spithill (USA) 1 - 4
Gavin Brady (ITA) 1 - 3
Jesper Radich (DEN) 1 - 4
Who beat who today:
Peter Gilmour bt Luc Pillot
Magnus Holmberg bt Jes Gram-Hansen
Ken Read bt Neville Wittey
Nicola Celon bt Jesper Radich
Magnus Holmberg bt Neville Wittey
Ken Read bt Jes-Gram Hansen
Nicola Celon bt Chris Dickson
James Spithill bt Jasper Radich
Chris Dickson bt Jasper Radich
Jes-Gram Haansen bt James Spithill
Andy Beadsworth bt Nicola Celon
Ken Read bt Gavin Brady
Jes-Gram Hansen bt Nicola Celon
Andy Beadsworth bt Ken Read
Petre Gilmour bt James Spithill
Luc Pillot bt Gavin Brady
Ken Read bt James Spithill
Peter Gilmour bt Gavin Brady
Neville Wittey bt Luc Pillot
Magnus Holmberg bt Andy Beadsworth
Gavin Brady bt Neville Wittey
Luc Pillot bt Andy Beadsworth
Magnus Holmberg bt Jesper Radich
Peter Gilmour bt Chris Dickson
Jesper Radich bt Andy Beadsworth
Luc Pillot bt Chris Dickson
Magnus Holmberg bt Nicola Celon
Peter Gilmour bt Jes Gram-Hansen
Peter Gilmour bt Nicola Celon
Jes Gram-Hansen bt Chris Dickson
Ken Read bt Luc Pillot
Magnus Holmberg bt James Spithill