Hashim Amla and Ben Geddes each notched hundreds as LV= Insurance County Championship leaders Surrey piled up 445 for five on the opening day of their match against Kent at the Kia Oval.
The hosts’ innings also saw Sam Curran contribute an explosive 53 not out from just 28 balls as stumps approached.
Amla, the 39-year-old former South Africa batter, and 20-year-old Geddes, playing just his fourth first-class match, hit 124 each and produced a third-wicket stand of 213 in 56 overs after Kent had asked Surrey to bat.
Simon Harmer took four evening wickets for Essex after Shane Snater’s 71 had dug them out of a hole in their clash against second-placed Hampshire at Chelmsford.
Snater became the county’s third-highest Championship run-scorer and recorded his third half-century this season to help Essex recover from 105 for seven to 238 all out.
Harmer then registered four for 23 as Hampshire slumped to 68 for six at the close.
Chris Dent’s second Championship century of the campaign failed to prevent Lancashire edging the first day of their match against Gloucestershire at Bristol.
Dent scored an unbeaten 109 off 246 balls, with 16 fours, but saw his team slip from 156 for two to close on 279 for seven.
Left-arm spinner Jack Morley claimed three for 79 from 23 overs on only his second first-class appearance.
Rob Keogh led the run-glut for Northamptonshire on day one of their clash with Warwickshire at Wantage Road, striking 130 with 20 fours as the hosts reached 420 for six.
Keogh shared a fifth-wicket stand of 161 with Josh Cobb (88), after Emilio Gay had caressed his way to 70 in the morning session.
In Division Two, table-toppers Nottinghamshire dominated the opening day of their meeting with second-placed Middlesex at Trent Bridge.
Haseeb Hameed made 101, and as Nottinghamshire closed on 378 for four, Lyndon James was within reach of his second century of 2022 on 90 not out, with skipper Steven Mullaney not far behind with an unbeaten 79.
Ed Barnard (131) struck his third hundred of the campaign as Worcestershire recovered from 63 for five against Glamorgan at New Road to post 271.
Pace bowler Joe Leach then made a treble breakthrough before the close in a deadly spell with the new ball as the visitors struggled to 32 for three.
Wayne Madsen starred as Derbyshire enjoyed a good first day against Sussex at Hove.
The home side had the better of the morning session when they reduced Derbyshire to 83 for four but Madsen hit back in style, progressing serenely to his 34th first-class century for the county, second only to Kim Barnett’s tally of 53.
At the close Madsen was 171 not out – the highest score by a Derbyshire batsman in Sussex – as they ended on 339 for five from 97 overs.