Alastair Cook struck a century as Essex made 303 for eight on day one of their Specsavers County Championship Division One clash with Kent at Chelmsford.
The former England captain's 125 was his first century in a competitive match since the memorable 147 he hit against India last year as he bowed out of international cricket.
Essex suffered a late collapse after Cook's dismissal, having been left on 175 for four when the 34-year-old was run out by Sean Dickson.
Among those subsequently ousted was Ravi Bopara, who contributed 61. Darren Stevens and Matthew Milnes finished the day with three wickets apiece.
Liam Norwell notched a half-century as Warwickshire fought back in their clash with champions Surrey at Edgbaston.
The home side were on 186 for eight, with Matt Dunn having taken a trio of wickets, before the partnership of Norwell (58 not out) and Henry Brookes (35 not out) helped them reach 275 by stumps without further loss.
Fidel Edwards claimed five wickets as Yorkshire were bowled out by Hampshire for 181 on a rain-affected first day at Headingley.
Edwards registered figures of five for 49 and there were also three wickets for James Fuller, including the scalp of Tom Kohler-Cadmore, who with 45 had put up the greatest resistance. Hampshire's reply was at 14 for one at close.
Division Two leaders Lancashire edged the opening day of their clash with Gloucestershire at Cheltenham College.
Saqib Mahmood finished with four for 48 as Lancashire bowled out Gloucestershire for 205. James Anderson chipped in with two wickets, including the final one to fall, as the hosts lost their final three batsmen without adding a single run.
By the time bad light brought a close three overs early, Lancashire had replied with 47 for two, losing Haseeb Hameed to a run out and Jake Lehmann, who was bowled by David Payne.
Opener Phil Salt scored his second successive century to put Sussex in a good position on day one of their match against Glamorgan.
Sussex were 208 for five at stumps – a lead of 22 after Glamorgan made 186. Having made 122 against Northamptonshire last week, Salt reached the fourth hundred of his career in the final over of the day. But, two balls later he lost concentration and was caught behind cutting at Dan Douthwaite for 103.
Salt was not the only opener to prosper, with Glamorgan's Nick Selman carrying his bat for the second time in his career. The 23-year-old was left unbeaten on 76 when Glamorgan, who have only won once in the Championship at Hove since 1975, were dismissed for 186 in 55.2 overs.
Tony Palladino bowled his side back into the match after Derbyshire had been dismissed for just 139 having chosen to bat first in their clash against Leicestershire.
The veteran seamer ended the day having taken three wickets as Leicestershire slipped to 55 for four in reply to Derbyshire's first innings total.
Earlier, Wayne Madsen had provided the only real resistance for the visitors as Mohammad Abbas and Chris Wright took three wickets apiece.
Middlesex hit back with the ball after being dismissed for 221 by Worcestershire at New Road.
Dawid Malan top scored with 45 for the visitors as Charlie Morris and Josh Tongue each claimed three wickets to give the Pears a strong start.
But Middlesex rallied to leave Worcestershire 64 for three at the close, trailing by 157 runs.
ga('create', 'UA-72310761-1', 'auto', {'name': 'pacontentapi'});
ga('pacontentapi.set', 'referrer', location.origin);
ga('pacontentapi.set', 'dimension1', 'By Press Association Sport staff');
ga('pacontentapi.set', 'dimension2', '768082b7-d7c4-40ee-be7b-42c5cd9ba7aa');
ga('pacontentapi.set', 'dimension3', 'paservice:sport,paservice:sport:uk');
ga('pacontentapi.set', 'dimension6', 'story');
ga('pacontentapi.set', 'dimension7', 'composite');
ga('pacontentapi.set', 'dimension8', null);
ga('pacontentapi.set', 'dimension9', 'sport:cricket');
ga('pacontentapi.send', 'pageview', { 'location': location.href, 'page': (location.pathname + location.search + location.hash), 'title': 'Alastair Cook hits century to put Essex on top against Kent'});