Yorkshire duo Adam Lyth and Adil Rashid claimed a record sixth-wicket stand as Lancashire faced the fight of their lives to avoid defeat in the LV= County Championship Division One Roses match against Yorkshire at Emirates Old Trafford.
Having seen the visitors pile up 610-6 declared, establishing a first-innings lead of 332, Lancashire were 144-2 at the close of the third day with Usman Khawaja unbeaten on 69.
However, Glen Chapple's batsmen will need to produce more of the same if they are to deny their title-chasing rivals and secure a vital five points in their own fight against relegation.
In the morning session Lyth (251) and Rashid (159) scored 130 runs in 32 overs as Yorkshire piled on the suffering for Chapple's attack.
Records then tumbled early in the afternoon as Lyth and Rashid took their partnership to 296, a sixth-wicket first-class record for Yorkshire, beating the 276 set by Maurice Leyland and Emmott Robinson at Swansea in 1926.
And, by the time Lyth drove Stephen Parry straight to Simon Kerrigan at mid on, he had made a career-best 251 off 446 balls in 11 minutes short of 10 hours and he was only one short of Darren Lehmann's Roses match record for an individual innings.
Rashid went on to make an unbeaten 159 and Yorkshire's total in 164 overs set yet another record for Roses matches.
Neil Dexter continued his excellent match to help steer Middlesex out of trouble on the third day against Warwickshire at Lord's.
After dismissing three of Warwickshire's top four batsmen on the first day, Dexter dug in with the bat on the third to help captain Chris Rogers shunt the match towards a draw.
In reply to the Bears' 362-8 declared, the home side were wobbling on 65-3 - still 148 short of the follow-on figure - before Rogers (85 from 170 balls with 12 fours) and Dexter (70 from 143 balls with seven fours and two sixes) repaired the damage.
Middlesex closed the third day on 310-6, with the match looking destined for a draw which would be much more useful to them than their opponents.
For Middlesex, a draw would mean useful points in their battle against the drop, but the visitors need to win to maintain pressure on leaders Yorkshire.
The Bears may come to rue the rain which washed out almost all the second day as a defining blow to their title hopes.
Ben Duckett's maiden first class century turned the match at Taunton and gave Northamptonshire a rare victory opportunity against Somerset going into the final day.
When the 19-year-old wicketkeeper walked to the crease, the division's bottom side were 194-6 and still 120 behind on first innings. By the time they declared on 448-9, it was with a lead of 134 and the England Under-19 player unbeaten on 144.
Duckett, whose previous best first-class score was 56, reached his hundred with a six over mid-wicket off Alfonso Thomas and went on to clear the ropes twice more as well as hitting 14 fours in his 210-ball innings.
Solid support from James Middlebrook (61) helped build a healthy advantage against a Somerset team who looked as though the end of the season could not come quickly enough. By the close, the hosts had reached 38 without loss in their second innings from nine overs.
A brilliant hundred by Paul Collingwood allowed Durham to set title-chasing Nottinghamshire a victory target of 375 at Chester-le-Street.
The visitors' chase did not start well and looked well beyond them when they slipped to 66-3, but Riki Wessels kept them afloat with an unbeaten 77 as they reached 197-4 - leaving a further 178 to be scored on the final day with six wickets standing.
The second man in Division One after Yorkshire's Adam Lyth to 1,000 championship runs, Wessels plundered 66 in the evening sunshine during a final session in which the only wicket to fall - that of Michael Lumb - came as a result of a spectacular catch.
Lumb had led a charmed life in reaching 58, but his luck ran out when a fierce slash was plucked out of the air by Calum MacLeod, leaping high to his right at gully.
Earlier, after recovering from 83-5, Durham reached the unexpected heights of 309 with Collingwood completing his first championship century for two years. It came off 219 balls.