Marco Giltrap has won the opening race of the Porsche Michelin GT3 Cup Challenge Australia second round at Symmons Plains after a dramatic final lap.

The winning margin of 3.9s was escalated by dramas to others on the last lap.

Sonic Racing’s Ronan Murphy crossed the line second ahead of Oscar Targett in his Porsche debut with Grove Racing.

From pole position, the Team Porsche New Zealand/Earl Bamber Motorsport Kiwi driver seized the lead from the outset as he edged out McElrea Racing’s Lachlan Bloxsom who slipped to third behind Sonic Motor Racing’s Marcos Flack.

TeckworkX Motorsport’s Aron Shields was fourth at the end of the first lap from Murphy who lost a couple of places at Turn 2 when he ran wide.

On the second lap, TekworkX’s Hamish Fitzsimmons copped a tap from behind at the Turn 4 hairpin and spun into the inside earth bank.

He was still there a lap later, causing the Safety Car to be deployed.

The cautionary period ran for seven laps as there was another incident. Ross McGregor and Eric Constantinidis had contact out of Turn 3, McGregor contacted the inside wall and stopped before Turn 4.

At the end of Lap 9, the race went green again where Giltrap mastered the start and created himself a small gap. Flack remained a second ahead of Shields while Bloxsom and Murphy argued over fourth.

Then out of the hairpin, Shields went into the back of Flack, hit Bloxsom and spun Shields.

The three-car incident enable Murphy to steal second ahead of Targett while EBM’s Zac Stichbury was fourth in front of Sonic’s Harrison Goodman.

Behind the five Pro drivers was Sam Shahin who was the leading Pro-Am.

He had dropped to eleventh before the incident and gained numerous spots as a recourse. Next was McElrea’s Tom McLennan and second in Pro-Am Brett Boulton.

Pro driver Tom Taplin finished ninth ahead of Pro-Am’s Andrew Goldie while in eleventh was Brad Carr and the winner of Class B for the older generation Porsches.

While Shields limped back to the pits, Flack finished 18th and Bloxsom 20th.

The Porsche Michelin GT3 Cup Challenge Australia second race is scheduled for 14:40 local time/AEST this afternoon before the final race on Sunday.