PERTH - A late counterpunch by big-hitting tailender Andrew Tweedie was not enough to save South Africa's KwaZulu Natal from an 81-run Champions Cup one-day cricket loss to Western Australia here last night.

Tweedie was left stranded on 70 not out after thumping 10 boundaries in his 67-ball knock when the South African team was bowled out for 189 in 47 overs in reply to the hosts' 4-270 off 50.

It was Western Australia's second straight tournament win and the hosts have all but stitched up a spot in Wednesday's final.

The inspiration of WA's first win - Test batsman Justin Langer who hit 119 not out against Indian champs Mumbai on Friday night - failed when the hosts were sent into bat yesterday.

Langer went for a duck but it failed to slow down WA as former Zimbabwe star Murray Goodwin (69 from 89 balls) led the charge.

Simon Katich (68 from 110), Michael Hussey (62 from 44) and Ryan Campbell (42 from 47) also joined in the carnage.

Best with the ball for the South Africans was Wade Wingfield with 2-42.

The South Africans' hopes of victory soon dissolved when the visitors slumped to 8-93 by the 29th over.

The only batsman to make an impression was opener Ashraf Mall (44 from 45 balls).

Then Tweedie stepped in.

He swung lustily to share a spirited 71-run stand with Kyle Bender (19) and 25 with last man Gary Gilder (1) before the South Africans' luck ran out.

Medium-pacer Darren Wates (3-27 from 8.3 overs) was the best with the ball for WA while Hussey (2-19) and Bradley Hogg (2-35) were also solid.

The South Africans have a chance to atone for their poor effort when they clash with Indian side Mumbai in day four tournament action today.

© 2001 AAP