Surrey enjoyed the perfect start to their LV= County Championship clash with Gloucestershire, bowling out their hosts for 112 before quickly building a first-innings lead at Bristol.
Paceman Matt Dunn claimed 4-37 while Jason Roy picked up 3-9 in just four overs as Gloucestershire were quickly made to regret their decision to bat first after winning the toss.
At one stage they were 67-8 in just the 21st over before Geraint Jones (28) and Matt Taylor, who made 24 from number 10 in the order, at least made sure they reached three figures in an innings that was over before lunch.
However their score was soon put into context by a superb unbroken opening stand of 186 between Rory Burns, who reached stumps unbeaten on 98, and Zafar Ansari (84 not out). Their efforts mean Surrey already lead by 74 runs with all 10 wickets still in hand.
Elsewhere in the second tier, the battle of the two counties currently occupying the promotion places saw Worcestershire work themselves into a strong position against Hampshire at New Road.
After finishing a rain-shortened opening day on 179-4, wicketkeeper Ben Cox registered his maiden first-class century to help the home team reach 402-9 before they declared in the closing stages of the evening session.
Cox made 104 while Alex Kervezee weighed in with 80 as Worcestershire claimed four bonus points. The decision by skipper Daryl Mitchell to cut short the innings quickly paid off, too, as Hampshire lost a wicket before stumps.
Jack Shantry had Michael Carberry caught off the first ball of the visitors' reply - they closed on 10-1 to leave themselves with plenty of work to do at the halfway stage of the fixture.
Essex earned themselves a first-innings advantage against Kent at Chelmsford, but with just one day remaining in the fixture time might be running out to force a positive result.
Tom Westley managed to add just two runs to his overnight score of 114 but Ravi Bopara moved from 112 to 162 before he was finally dismissed, the England international caught behind off the bowling of Ben Harmison.
James Foster made 46 while Tymal Mills contributed a breezy 30 down the order before becoming the fifth victim for seamer Mitchell Claydon. Essex ended up making 440, giving them a lead of 53.
Kent reduced the deficit to 18 as opening pair Rob Key and Daniel Bell-Drummond came through a tricky 15-over period unscathed.
David Wainwright made his highest score for Derbyshire to help his employers reach 279-8 in reply to Leicestershire's total of 311 at Grace Road.
Former Yorkshire spinner Wainwright reached the close unbeaten on 83 - he has previously made two first-class hundreds before switching counties - having helped rescue an innings that was spluttering at 115-6.
Alex Hughes made 60 during a seventh-wicket stand worth 91 and debutant Tom Taylor added 20 not out to put Derbyshire within touching distance of parity.