Two sides that are very much contenders for the top four come up against each other here, with the winner certain to make a big step towards qualification for the semi-finals.
With the Bulls, Stormers and Crusaders all looking a good bet for the top 4, whichever team wins here should keep themselves well in the running to claim that coveted fourth spot.
Ref: Jaco Peyper (South Africa)
ARs: Paul Marks (Australia), Lourens van der Merwe (South Africa)
TMO: Matthew Goddard (Australia)
Venue: Canberra Stadium
Kick-off: 10h40 SA Time, 08h40 GMT
Brumbies: 15 Adam Ashley-Cooper, 14 Pat McCabe, 13 Stirling Mortlock, 12 Matt Giteau, 11 Francis Fainifo, 10 Matt Toomua, 9 Josh Valentine, 8 Stephen Hoiles (captain), 7 Michael Hooper, 6 Rocky Elsom, 5 Mitchell Chapman, 4 Ben Hand, 3 Salesi Ma’afu, 2 Stephen Moore, 1 Ben Alexander.
Replacements: 16 Huia Edmonds, 17 Guy Shepherdson, 18 Mark Chisholm, 19 Colby Faingaa, 20 Patrick Phibbs, 21 Tyrone Smith, 22 Julian Huxley.
Chiefs: 15 Mils Muliaina (captain), 14 Lelia Masaga, 13 Richard Kahui, 12 Jackson Willison, 11 Sitiveni Sivivatu, 10 Stephen Donald, 9 Brendon Leonard, 8 Sione Lauaki, 7 Tanerau Latimer, 6 Liam Messam, 5 Culum Retallick, 4 Craig Clarke, 3 Ben Afeaki, 2 Aled de Malmanche, 1 Sona Taumalolo.
Replacements: 16 Hika Elliot, 17 Nathan White, 18 Jarrad Hoeata, 19 Luke Braid, 20 Junior Poluleuligaga, 21 Mike Delany, 22 Tim Nanai-Williams.