Plunkett and Hales among stars
Liam Plunkett helped Yorkshire to a County Championship win over Northamptonshire on Tuesday, while Alex Hales hit a ton for Nottinghamshire.
Hosts Northamptonshire began on 66 for three in pursuit of an improbable 432 for victory but, even with a delayed start to proceedings, they only lasted until mid-afternoon before being bowled out for 160.
Plunkett led the way as he claimed four of the final five wickets to fall as Yorkshire sealed victory by 271 runs, and in the process inflict a fifth defeat in six matches on Division One strugglers Northamptonshire.
At Old Trafford all-rounder Peter Trego starred with the ball as Somerset chased an innings victory against Lancashire.
The experienced Trego and Somerset's young guns Craig Overton and George Dockrell each took three wickets apiece as Lancashire were bowled out for 203 in pursuit of Somerset's 420.
Then, after the home side were made to follow on, Trego dismissed Alex Davies, Paul Horton and Ashwell Prince cheaply to reduce Lancashire to 95 for three at the close on day three - still trailing by 122.
At Hove Alex Hales bludgeoned his first Championship century in nearly two years for Nottinghamshire to show England's One-Day International side what they were missing.
Hales blitzed 167 from 133 balls as Nottinghamshire took control, closing the third day with a commanding 404-run lead after declaring on 336 for four in their second innings.
Before that Sussex's Ed Joyce turned an overnight 104 into an unbeaten 164 in his side's first-innings total of 355 all out, but it was Hales' big hitting that dominated proceedings.
Middlesex opener Sam Robson stood firm as Durham piled on the pressure in search of their first championship win of the season.
Robson finished day three at Chester-le-Street on 42 not out with his side on 90 for two in their second innings and still trailing by 148 after being asked to follow on.
Chris Rushworth had earlier trapped Chris Rogers leg before for one with the score on five before Keaton Jennings took a fine diving catch off the bowling of Mark Wood to remove Dawid Malan and leave the champions in the driving seat heading into the final day.
In Division Two, Hampshire captain Jimmy Adams hit his second half-century of the match against bottom side Derbyshire at the Ageas Bowl.
Adams, having scored 60 on day one, made 67 to help Hampshire reach 214 for five declared, which set Derbyshire what looks a testing 346-run victory chase. By close of play, the visitors had made 31 without loss.
Geraint Jones rolled back the years with a brutal 93 for Gloucestershire, but Leicestershire hold a slender 21-run advantage going into the final day at Grace Road.
Will Gidman also added a half-century to his five-wicket haul for the visitors in reply to Leicestershire's 269 all out but a late collapse saw them dismissed for 260. Leicestershire reached 12 without loss in their second innings, before bad light and rain brought an early end to proceedings.
Jack Shantry took six wickets as Worcestershire forced Surrey to follow-on and take a 159-run lead into the final day at the Kia Oval.
Shantry's emphatic display included four wickets in 11 balls, while Zafar Ansari's was stranded on an unbeaten 77 in Surrey's first innings and ended on 50 not out at the close as his side moved to 111 for three.
Will Bragg helped edge Glamorgan into a 152-run lead over Essex on a rain-hit third day at Chelmsford, where home bowler Reece Topley claimed his 10th wicket of the match.
Bragg, who had scored 93 in the first innings, fell just short of a second half-century when he was caught on 46, before 20-year- old Topley punished Glamorgan's middle order as the visitors finished the day on 188 for eight.