Alex Lees and Ollie Robinson scored contrasting day-one centuries as Durham piled on the runs at Vitality County Championship title rivals Essex.
Opener Lees commanded the crease in his 220-ball 113, while Robinson took the bowlers on with gusto as he struck four sixes and 16 fours in his unbeaten 146 – both grabbing their second hundreds of the campaign – to help Durham rack up 445 for four.
David Bedingham missed out on a fifth three-figure score on the bounce but assisted the centurions with a sublime 65, as he passed 800 Championship runs this year.
Essex’s only positive on an otherwise dispiriting day at Chelmsford was overseas debutant Eathan Bosch claiming two wickets.
It was normal service resumed for leaders and champions Surrey against Worcestershire as they racked up 340 for five.
Fifties from Dom Sibley (76) and Jamie Smith (86) laid the foundations before Dan Lawrence and Ben Foakes increased the tempo during the final session during a stand of 131 in 35 overs.
Foakes fell for 52 just before the close – to a fourth catch for Adam Hose – but Lawrence remained undefeated on 91.
Fast bowler Olly Stone’s unbeaten 74 led a Nottinghamshire recovery from 190 for seven to 326 for eight against Somerset at Trent Bridge.
He shared in an eighth-wicket stand of 112 with Calvin Harrison to give the day a different complexion after Joe Clarke (51) and Jack Haynes (55) had guided the hosts to 179 for three.
Somerset seamer Kasey Aldridge was the main driver of a mid-innings collapse that saw four wickets fall for 11 runs, finishing with four for 90, while South African seamer Migael Pretorius took three for 73.
Lancashire finished on 38 for one at Canterbury, trailing fellow Division One strugglers Kent by 206 runs.
George Balderson and Nathan Lyon took three wickets apiece as Kent were bowled out for 244 before the vistors lost captain Keaton Jennings for a duck in reply.
John Simpson’s 180 not out led Division Two leaders Sussex to a mammoth 431 for seven against Leicestershire, with opener Oli Carter contributing 96 and Nathan McAndrew an unbeaten 51 after the home side had been asked to bat at Hove.
Adam Lyth continued his Scarborough love affair with a fourth Championship hundred on his home ground as he and opening partner Fin Bean shared in a stand of 307 to ensure Yorkshire dominated day one against Gloucestershire.
The former England opener scored 129 while Bean struck six sixes and 18 fours in his 164 as Yorkshire closed on 348 for three from 96 overs after being sent in.
Glamorgan finished their opening day 243 runs behind Northamptonshire on 36 without loss after bowling their visitors out for 279, Timm van der Gugten, James Harris and Andy Gorvin claiming three wickets apiece.
Warwickshire trio Olly Hannon-Dalby, Ed Barnard and Craig Miles also took three wickets each as Hampshire were bowled out for 298 after choosing to bat on a good pitch at Edgbaston. The hosts finished on 51 for two.
Ryan Higgins again proved the saviour of Middlesex as the hosts fought back from early trouble to post 342 for seven against Derbyshire at Lord’s.
The Zimbabwe-born all-rounder battled to a fourth century of the season, reaching his ton with a six into the Mound Stand as the hosts recovered from 189 for six.
He finished unbeaten on 107 having shared in 112-run unbroken stand with Seaxes skipper Toby Roland-Jones, whose 51 not out was his first championship half-century for 21 months.
