Leaders Warwickshire's bid for a potentially-decisive victory in the LV= County Championship Division One title race were all but ended by an Alex Hales century against Nottinghamshire at Edgbaston.
The Bears began the day hoping to quickly bundle their visitors out and enforce the follow-on, but Hales and Chris Read scuppered those plans as Nottinghamshire reached lunch on 322 for six.
That left them needing just another 33 runs to avoid being sent straight back and, with Hales still unbeaten on 139, a draw looked the most likely outcome.
Read had earlier fallen five runs short of his century after he was stumped off the bowling of on-loan Ian Blackwell.
With Warwickshire already 17 points ahead of Sussex, who are inactive this week, their lead is set to grow only marginally with the three points for the draw and any added bonus points on Friday afternoon.
Worcestershire's survival bid took another blow as they crashed to 125 for seven against Middlesex. Toby Roland-Jones (five for 46) completed a 10-wicket match-haul that left the Pears with a lead of just 142.
Champions Lancashire, who sit bottom of the table, were left to pick up as many bonus points as they could after rain washed out most of their match with Durham at Liverpool.
Durham were 291 for six at lunch after Simon Kerrigan grabbed both wickets on Friday morning to have four for 75.
Surrey, who sit closest to the drop zone, looked unlikely to push for victory against Somerset after progressing to 153 for two at Taunton.
Surrey therefore had a lead of 176 but with Kevin Pietersen at the crease, unbeaten on 28, an acceleration could yet happen.