Moeen Ali furthered his claims for a place in England's Test XI with a superb unbeaten century for Worcestershire on the opening day of their Division Two fixture against Surrey.
The all-rounder was unbeaten on 138 to help the visitors reach 329-4 by stumps at the Oval, vindicating skipper Daryl Mitchell's decision to bat first after winning the toss.
Mitchell himself continued his fine form in first-class cricket this year with 62 at the top of the order, while fellow opener Matt Pardoe (52) also made a half-century during a first-wicket stand worth 88.
Moeen added a further 87 with his captain and then put on 114 with Tom Fell, who weighed in with 42. Chris Tremlett finished as the pick of Surrey's attack, claiming 2-36 from 20 overs.
Elsewhere in the second tier, leaders Hampshire cashed in on visiting captain Wayne Madsen's decision to bowl first by making 332-7 against Derbyshire at the Ageas Bowl.
Openers Jimmy Adams (60) and Will Smith (82) shared a stand of 110, though the hosts then lost three wickets for eight runs, Antonio Palladino claiming them all on his way to figures of 4-83.
However, Smith - who faced 190 deliveries during nearly four hours at the crease - added 109 with Adam Wheather before Palladino struck again, dismissing the former leg before.
Wheater failed to reach three figures himself, falling to Mark Footitt for 87, but Sean Ervine's 47 helped carry Hampshire to 300 and beyond. He was removed in the closing stages by Tim Groenewald, who then also sent back Matt Coles for eight.
Reece Topley marked his first appearance of the season in the LV= County Championship by taking 6-41 as Essex bowled out Glamorgan for 244 at Chelmsford.
The left-armer seamer, fit again after suffering a stress fracture of the back in the winter, yorked Tom Lancefield in only the second over of the day and after dismissing Ben Wright after lunch, returned with the second new ball to pick up four wickets in five overs.
But it was leg-spinner Tom Craddock, given the chance to play after Monty Panesar was dropped for "breaching team rules on timekeeping", who claimed the crucial scalp, getting Will Bragg caught by Mark Pettini for 93.
Jesse Ryder also claimed two wickets as Glamorgan slumped from 162-3 to be dismissed in 95.2 overs. Chris Cooke was the last man to fall, caught by Ryder off the impressive Topley.