Warwickshire and Sussex both claimed 10 wickets on a chaotic opening day of their LV= County Championship Division One clash at Edgbaston.
Jonathan Trott's first competitive outing since he left England's tour of Australia came on a chaotic day that saw 20 wickets fall and Warwickshire skittled by Sussex for just 87.
Trott's 37 was easily Warwickshire's highest score, as they failed to reach three figures, while his effort was later put in the shade by Ed Joyce, whose 117 underpinned Sussex's total of 229.
Chris Jordan and Steve Magoffin both claimed bowling figures of 3-15 while Jon Lewis returned 3-18 before Joyce's century help Sussex to establish a 142-run first-innings lead.
For Warwickshire, Keith Barker (3-52), Chris Woakes (2-31) and Rikki Clarke (2-33) helped the Bears battle back and collect maximum bowling points, however they have work to do to overturn their first-innings deficit.
Middlesex seamers Steven Finn and James Harris shared eight wickets as Nottinghamshire reached 315-8 after the first day of their clash at Lord's.
Six Nottinghamshire players posted 20 or higher at Lords, with James Taylor top-scoring on 62 before being trapped lbw by James Harris, who took 4-80.
Taylor hit 13 fours from his 84 balls and having settled at the crease, he will have been disappointed not to have made a bigger score.
Finn, who took 6-80 in last week's crushing defeat at Sussex, maintained his fine start to the season with 4-87, claiming the wickets of Steven Mullaney (52), Michael Lumb (17), Riki Wessels (58) and Chris Read (40).
Durham got the defence of their title off to a steady start against newcomers Northamptonshire, reaching stumps on 265-5 after opting to bat first at Wantage Road.
Northants were promoted as Division Two runners up last season and could not have been handed a much tougher task on their return to the top flight, but they bowled well with Maurice Chambers taking 2-52
Keaton Jennings and Michael Richardson both made half-centuries for Durham but their hopes for a big first-innings total will largely rest with Phil Mustard, who had advanced to 63 not out at stumps.
Yorkshire began their Division One campaign with a dominant batting display to put the pressure on Somerset on the opening day of their Division One clash at Taunton.
The White Rose county are looking to go one better than the runners-up spot they achieved last season, and the early signs were promising as half-centuries from Adam Lyth (85), Gary Ballance (77) and Adil Rashid (84no) saw them reach 342-5 at stumps and claim three bonus batting points.
Somerset, for whom Craig Meschede took 3-82, were left to rue their decision to bowl first as batting conditions improved after the first hour.