Surrey have secured the Vitality County Championship for a third year running after title rivals Somerset fell to a 168-run defeat against Lancashire.
A 10-wicket win over Durham on Thursday left Surrey on the verge of a successful title defence and leaving Somerset needing to beat relegation-threatened Lancashire to take the title race to the final week of the season.
Somerset went into the final day at Old Trafford on 204-6, still 189 runs short of their victory target, with their hopes suffering an immediate setback when captain Lewis Gregory was bowled by Luke Wells (4-36) from the opening ball of the morning.
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Jamie Overton (four) was trapped lbw by Anderson Phillip (3-81) the following over and Brett Randell (nine) was clean bowled soon by Wells soon after, before Phillips removed James Rew (31) for the final wicket to see the visitors bowled for 224.
It took Lancashire little over 30 minutes on day four to wrap up their victory, which means Surrey have now become the first county to win three straight championships since Yorkshire between 1966-1968.
Lancashire stay ninth in the Division One table but still with an outside chance of leapfrogging Nottinghamshire on the final day of the season and avoiding relegation, while Somerset dropped to third after Hampshire wrapped up a 235-run victory over Worcestershire.
Worcestershire resumed on 117-5, still 277 runs short of victory, with Kyle Abbott (5-58) dismissing Ethan Brookes (30) and opener Jake Libby (57) in successive overs as of a four-wicket spell to see them bowled out for 158.
In Division Two, Yorkshire moved a big step closer to promotion after taking the final three wickets required to close out a 186-run victory over Glamorgan and move second in the table.
A 39-run eighth-wicket stand came to an abrupt halt when Matthew Fisher dismissed Asa Tribe (58) and Andy Gorvin (0) in the same over, before Andy Gorvin (49) was bowled by Jordan Thompson to complete a convincing win for Yorkshire.
What's next?
The final round of the Vitality County Championship fixtures begins on Thursday, with champions Surrey away at Essex and Somerset hosting Hampshire at Taunton.
Lancashire need to win away at Worcestershire to have any chance of staying in Division One, although will be relegated should Nottinghamshire avoid defeat at home to Warwickshire and earn two extra points.
Yorkshire can secure promotion back to the top division with 10 points or more at home to Northamptonshire, regardless of Middlesex's result against already-promoted Sussex. Sussex only need five more points to guarantee the title.