Canberra - Jake White's Brumbies beat the hapless Waratahs 35-6 in a Super Rugby clash on Saturday despite losing openside flanker David Pocock to what could be a serious knee injury.

The Brumbies made light of the loss of Pocock, who limped off early with what commentators suggested was a torn anterior cruciate ligament, as Ben Mowen and Christian Lealiifano touched down to help give the home side a 21-6 half-time lead.

Henry Speight and replacement Robbie Coleman scored further tries in the final 10 minutes to secure a bonus point and round off a third straight win that cements the Brumbies' status as the pacesetters in the Australian conference.

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The loss of Pocock for any length of time could hit the Brumbies hopes of mounting a title challenge, although former Wallabies flanker George Smith impressed as Pocock's replacement on his debut after joining on a short-term contract.

"George Smith is phenomenal," Brumbies coach White said. "It was a stroke of genius in terms of getting him here. I don't wish anything on David but at the same time there's no doubt his (Smith's) presence and what he did tonight just shows what a talent he is."

However, Smith and the Brumbies will find few sides as obliging as the Waratahs, who conceded a string of soft penalties at the breakdown, struggled at the lineout and showed little sign of breaching the home defence.

The Brumbies were clinical in exploiting their fellow Australians' deficiencies and have yet to concede in the second half in this season's tournament.

"I can't praise them enough," White said. "They're maturing as a team and it's fantastic to watch."

Wearing special yellow jerseys to mark the Australian capital's centenary celebrations, the Brumbies were already 9-0 ahead when Smith replaced Pocock thanks to three penalties from Lealiifano.

They barely broke stride despite losing Pocock, who watched the remainder of the match from the sidelines with his left leg raised and an ice pack occasionally strapped to the damaged joint.

The first try came following a knock on from Waratahs scrumhalf Brendan McKibbin deep in Brumbies territory. The home side drove play up the other end and, from a five-metre lineout, Mowen grounded after being shoved over the line.

Lealiifano missed the conversion but claimed a try of his own after Jesse Mogg sent through a smart grubber kick.

A yellow card to Brumbies lock Sam Carter for failing to clear the ruck allowed McKibbin to land his second penalty just before the interval but there were no more points until both teams were down to 14 men.

Opposing props Ben Alexander and Benn Robinson were sent to the sin bin for offences at a ruck and, with gaps developing, Speight surged to the left corner off a pass from Fotu Auelua.

Lealiifano completed an 18-point haul with the conversion before Mogg danced past several opponents and offloaded to Coleman, who collected his own chip over the next man and scored.

Scorers:

Brumbies:

Tries: Ben Mowen, Christian Lealiifano, Henry Speight and Robbie Coleman.

Conversions: Lealiifano (3)

Penalties: Lealiifano (3)

Waratahs:

Penalties: Brendan McKibbin (2)

Teams:

Brumbies:

15 Jesse Mogg, 14 Henry Speight, 13 Andrew Smith, 12 Christian Lealiifano, 11 Clyde Rathbone, 10 Matt Toomua, 9 Nic White, 8 Ben Mowen (captain), 7 David Pocock, 6 Peter Kimlin, 5 Sam Carter, 4 Scott Fardy, 3 Dan Palmer, 2 Stephen Moore, 1 Ben Alexander

Substitutes: 16 Siliva Siliva, 17 Scott Sio, 18 Fotu Auelua, 19 George Smith, 20 Ian Prior, 21 Robbie Coleman, 22 Joe Tomane

Waratahs:

15 Ben Volavola, 14 Israel Folau, 13 Adam Ashley-Cooper, 12 Tom Carter, 11 Drew Mitchell, 10 Bernard Foley, 9 Brendan McKibbin, 8 Dave Dennis, 7 Michael Hooper, 6 Mitchell Chapman, 5 Kane Douglas, 4 Sitaleki Timani, 3 Sekope Kepu, 2 Tatafu Polota-Nau, 1 Benn Robinson.

Substitutes: 16 Luke Holmes, 17 Paddy Ryan, 18 Greg Peterson, 19 Lopeti Timani, 20 Pat McCutcheon, 21 Matt Lucas, 22 Lachie Turner