Title-chasing Yorkshire made light of losing the toss and clearly held the upper hand by the close of the first day of the LV= County Championship Division One Roses match at Emirates Old Trafford.
Andrew Gale's bowlers dismissed Lancashire for what seems a below-par total of 278 before openers Adam Lyth and Alex Lees added 61 for no wicket in 19 overs by close of play.
Ryan Sidebottom, Jack Brooks and Adil Rashid all took three wickets on a day which did nothing to ease the home side's relegation fears.
Warwickshire kept their hopes of a treble very much alive by reaching 338 for six against Middlesex on the opening day at Lord's.
Put in on a pitch offering assistance to the seamers, Warwickshire were lifted into command by Rikki Clarke who ended the day unbeaten on 93 off 134 balls.
He frustrated a Middlesex side which several times had their opponents vulnerable - notably at 99 for three and 205 for six - but never induced the sort of collapse which could shape the match.
They have not beaten the Bears in 16 attempts in the championship but have a chance to end that barren run here on a result pitch. But Warwickshire batted with collective defiance.
Every batsman from one to eight reached double figures and then in the last session seventh-wicket pair Clarke and Keith Barker (60 from 102 balls) added an unbroken 133.
Alex Barrow's career-best 88 helped Somerset recover from a poor start to post 314 all out on the opening day of the match with Northamptonshire at Taunton.
Having lost the toss, the hosts plunged to 70 for four after David Willey had removed both openers cheaply. But 22-year-old Barrow then counter-attacked with 18 fours in sharing a fifth-wicket stand of 153 with Nick Compton, who made 79.
Seamers Willey (four for 64) and Azharullah (three for 69) capitalised on a green pitch, while the batsmen enjoyed the benefit of uninterrupted sunshine.
By the close Northants had replied with 39 for no wicket and were entitled to feel on top.
Bowlers were on top at Chester-le-Street as 14 wickets fell on the opening day between Durham and Nottinghamshire.
On a pitch offering some encouragement to the seamers, title-chasing Nottinghamshire had cause for satisfaction in dismissing their struggling hosts for 253 after losing the toss, but they then slumped to 66 for four in reply as Durham fought back.
In Division Two, Charlie Morris claimed his 50th first-class wicket of the season as Worcestershire edged closer to promotion against Derbyshire at Derby.
The seamer bowled with control to finish with impressive figures of 4 for 43 from 23 overs to undermine Derbyshire after half-centuries from Billy Godleman and skipper Wayne Madsen had put them in a strong position.
But the Division Two leaders hit back after lunch and secured two bowling points as the home side slipped from 153 for one to 262 for seven before an unbeaten 73 from from Alex Hughes steered Derbyshire to 323 for eight at the close.
Angus Robson hit a century as Leicestershire got off to a good start against Hampshire at the Rose Bowl in Southampton.
The visitors won the toss and elected to bat first but lost Greg Smith early on before his fellow opener claimed his ton from 216 balls in 263 minutes - including 15 fours - before he was caught by Sean Ervine for 115 as Leicestershire went on to post 301 for nine at stumps.
Chris Cooke scored a superb maiden first-class century to keep Kent's attack at bay and guide Glamorgan to 329 all out on the opening day at Canterbury.
The 28-year-old South African-born batsman was last out for 171 after holding Glamorgan's first innings together against a Kent team still with an outside chance of promotion and aiming to win three of their last four championship games.
At stumps, Kent were one without loss in their first innings, after four overs.