Melbourne have blown the Super Rugby AU competition wide open after handing the Brumbies their first defeat of the season in a thumping 30-12 victory.

The Brumbies arrived for their Friday night clash at Leichhardt Stadium with a commanding seven-point lead at the top of the Super Rugby AU ladder, but left shell-shocked.

With playmakers Matt Toomua and Andrew Deegan playing smart wet-weather rugby in Sydney, the Rebels were in full control throughout while the Brumbies were uncharacteristically poor.

Fullback Reece Hodge showed their intent when he scored the first of his two tries in the third minute as they shifted the ball wide.

The lead was extended to 12-0 when Marika Koroibete kicked a loose ball ahead and raced Andy Muirhead downfield with the Brumbies winger failing to pick it up in the greasy conditions before Koroibete managed to offload to flanker Brad Wilkin.

Some rare joy of the night for the Canberra team came two minutes later when they mauled the ball off an attacking line-out, with halfback Joe Powell scooting across the tryline.

But the Rebels were up for the fight and responded soon after through Hodge’s second and they were out to 27-7 by halftime.

The Brumbies had to toil a man down when flanker Tom Cusack was yellow-carded for repeated infringements right on halftime but their defence at least held firm in his absence.

They can take heart that they limited Melbourne to a sole penalty kick in the second half despite plenty of pressure and managed a late try through Will Miller.

Both teams finished with some injury concerns with Brumbies prop Scott Sio limping off, as did Rebels backrower Rob Leota, while Melbourne hooker Jordan Uelese and Brumbies prop Tom Ross both suffered head knocks.