Western Australia's last batsman Brad Williams struck a six with two balls to spare to give the Warriors a stunning win over South Australia in their limited overs day-night cricket match at Adelaide Oval tonight.

Chasing SA's 7-235 from 50 overs, the Warriors passed the target, reaching 237 from 49.4 overs with just one wicket in hand.

Williams came in with four runs required to win off the final four balls - with left-arm spinner Brad Young bowling - and failed to score off the first ball he faced.

But he struck a massive six which easily cleared the mid-wicket boundary off the next ball to give WA the victory, which had looked highly unlikely at several stages throughout their innings.

Openers Chris Rogers (39 from 53 balls) and Ryan Campbell (20 from 22 balls) got the Warriors off to a flying start to be 0-39 eight overs into the innings.

They were particularly severe on SA debutant Matthew King, whose opening four over spell cost 32 runs, including 15 from his fourth over.

But Mark Harrity replaced him and picked up the wicket of Campbell in his second over and then dismissed Rogers in his fourth over, on his way to 2-40 from 10 overs, while young paceman Paul Rofe conceded just 23 from his 10 overs at the other end.

The required run-rate was up to almost six per over 28 overs into the innings and, when SA captain Darren Lehmann had WA counterpart Simon Katich stumped in the 35th over, the Warriors were in deep trouble.

The required rate was up to eight per over with 11 overs remaining with SA looking headed for victory.

But Stuart Karppinen smashed 22 from 22 balls to keep WA in the match, with 12 coming from the 40th over the innings bowled by Mike Smith.

Wickets fell steadily as the run-chase continued, but it did not slow the Warriors, with Smith conceding 16 runs in the 45th over.

With three overs to go WA needed just 17 runs with three wickets in hand.

Young trapped Marcus North (17 off 16 balls) lbw in the 48th over while conceding just four runs to make it 13 needed from two overs with two wickets remaining.

Smith conceded seven runs in the 49th over to Brad Hogg and Matthew Nicholson, meaning just six runs were needed in Young's last over.

A wide on the first ball meant WA needed five off six balls, but Hogg was run out off the next ball, leaving Nicholson and Williams to score five runs from five balls.

Nicholson scored a single, and Williams blocked the next ball straight back to Young, building the tension, before striking the killer blow with the next ball. Young finished with 4-55.

Greg Blewett was named man of the match for his top score of 73 from 101 balls in SA's innings.

© 2001 AAP