The Bulls finished day three of the Sheffield Shield game on 5-111 in their second innings, still needing another 24 to make the Blues bat again.

Queensland captain Khawaja, who had scored just 81 runs at an average of 11.57 from his seven previous Shield innings this season, notched his highest first-class score of the campaign, finishing the day on 53 not out.

No Bulls batsman outside of Khawaja made more than 17 on Monday, as Sheffield Shield ladder leaders NSW closed in on a fifth outright win in six games.

He has faced 113 balls in his defiant 168-minute innings, striking four boundaries, since starting his innings before tea.

"He's gong to be a big challenge for us to get out tomorrow and I think he's obviously the key wicket," NSW allrounder Sean Abbott told AAP.

"We'll be fighting hard to get him nice and early in the morning and look to wrap things up and get batting if we need (to), hopefully with not too many runs to chase down."

The second-placed Bulls trailed by 135 on first innings after dismissing the Blues for 375 mid-afternoon.

Abbott (86) and NSW captain Peter Nevill (88 not out) batted throughout the first session and put on 159 in a pivotal sixth-wicket partnership.

"The first few hours this morning could have gone one way or the other, so I think it was a pretty important partnership with Nevvy, especially before lunch," said Abbott, who made his highest first-class score.

Test squad pacemen Michael Neser ripped out the bottom half of the NSW order by taking 4-8 in 29 balls to finish with 4-60 off 30.5 overs.

Queensland's second innings got off to a bad start with Blues veteran Stephen O'Keefe marking his 35th birthday by running out Bryce Street with a direct hit from midwicket before tea.

The Blues claimed four more wickets in the final session, taken by different bowlers.

Abbott, who was man-of-the match in Australia's T20 win over Pakistan in Perth last month, supplemented his batting effort by taking 1-10 off 12 overs.

Australian Associated Press