Western Australian pacemen Matt Nicholson and Jo Angel stormed through the South Australian lower order to dismiss the Redbacks for 206 and claim a first innings lead of 21 on day two of their four day match at Adelaide Oval today.

Nicholson finished with 4-58 and Angel with 3-48 as SA crashed from a position of strength at 3-163 to lose its last seven wickets for 43.

South Australian all-rounder Ben Johnson, in his first four-day state match of the season, valiantly tried to guide the Redbacks to first innings points, opening the batting and carrying his bat through the innings of almost six hours to finish unbeaten on 121 from 243 balls.

Chasing WA's first innings of 227, SA started the day at 0-6 but was soon 3-31 after Brad Williams dismissed Bradley Young for two and Greg Blewett for a duck and Nicholson picked up the scalp of SA skipper Darren Lehmann for 12.

Johnson, who was only called into the side to replace regular openers Jeff Vaughan (concussion) and David Fitzgerald (illness), combined with Chris Davies (52) for a three-hour fourth wicket partnership of 132 runs, which seemed likely to deny WA first innings points.

But it was the only partnership of substance in the innings - the next best was 23 between Lehmann and Davies for the third wicket - and ended when Davies attempted a suicide single to 12th man Kade Harvey at mid-on on the last ball before tea.

That wicket sparked a remarkable batting collapse, with Nicholson picking up three wickets in the first five overs after tea, before Angel snared the last three wickets to clean up the tail.

No player other than Johnson, Davies and Lehmann (12) managed more than two for SA.

Johnson said the run-out of Davies was the crucial moment in the day's play.

"It was obviously disappointing when he ran himself out, that really was the turning point," he said.

"Up until then we were clearly in control but we were unable to get another partnership to happen."

WA was 0-23 at stumps in its second innings, an overall lead of 44, with Scott Meuleman on 14 and Mike Hussey on seven.

© 2001 AAP