Persistent rain washed out the entire first session of play on Sunday, and threatens to rob NSW of a shot at an outright victory in their Sheffield Shield clash with Western Australia in Sydney.

The Blues arrived at Blacktown International Sportspark on day four with WA on 8-211, with a second-innings lead of just 109 runs.

Captain Stephen O’Keefe said his side were confident of claiming the final two wickets and chasing down a small total for their third outright win of the season.

But with rain forecast throughout the rest of the day, the chance of play appears slim.

Once the rain stops, it will take roughly 45 minutes for the ground to be prepared for play.

If play resumes, the Warriors will continue their second innings with debutant offspinner Ashton Agar unbeaten on 29 with fast bowler Jason Behrendorff not out four.

The Shield’s worst-performed side were torn apart by O’Keefe on Saturday, losing 5-15 in one 12-over period with the Blues skipper holding figures of 4-47.

Nathan Coulter-Nile delivered some lusty blows in his quickfire 42 off 39, taking particular liking to Steve Smith (0-26 off three overs).