An undefeated 108 from Ned Eckersley helped Leicestershire blunt Worcestershire's hopes of pressing for a win with their spinners in the rain-hit Division Two clash at New Road.
The home side set out their stall by declaring at 320-7 after a maiden championship century for Thilan Samaraweera, but Eckersley's knock took Leicestershire to 229-2, a deficit of 91 when the third day ended because of bad light.
The 23-year-old Eckersley's third first-class century was a well-crafted innings with 14 fours from 186 balls.
He needed to be watchful in facing Shaaiq Choudhry and Moeen Ali in helpful conditions for the Worcestershire spin pair.
Slow left-armer Choudhry, appearing in a home championship match for the first time, made a breakthrough by bowling Michael Thornely (17) after an opening partnership of 51 with Niall O'Brien.
In general, however, Leicestershire played the slow bowlers well and O'Brien, although restricted to a couple of fours, featured in a stand of 55 with Eckersley before he was bowled for 46.
That was Moeen's 100th first-class wicket and soon afterwards he might have had another when Ramnaresh Sarwan was dropped at short mid-wicket.
That proved to be costly for Worcestershire as the West Indies batsman - he will be playing in the Champions Trophy next month - reached 46 not out and helped Eckersley through to his third first-class hundred.
Their stand was worth 123 at the close but the overall tempo for the match has been stuck at a fraction under three runs an over and looks to be heading for a draw on Saturday.