A hat-trick from Steve Harmison helped Durham claim a seven-wicket victory over Sussex, who slipped to their first County Championship First Division defeat of the season.
Acting captain Matt Prior produced a sparkling unbeaten 133 but Sussex were let down by fragile batting at the top of the order as they were bowled out for 212.
Harmison finished with figures of four for 75 with support from fellow Durham seamer Callum Thorp who collected four for 77.
That left Durham needing 126 to win and Michael Di Venuto set them up with a hard hitting 60 after Jason Lowry struck early on to remove Phil Mustard for a duck and first innings centurion Will Smith for nine.
Neil McKenzie (41 not out) and skipper Dale Benkenstein unbeaten on seven eased Durham home with a day to spare as the title holders suffered their first championship home defeat since the last game of the 2004 season.
A fine 85 from Ravi Bopara failed to stop Worcestershire from securing their first Division Two win of the season with a 75-run triumph over Essex at New Road.
Bopara put on 111 for the sixth wicket with James Foster after the visitors had been left a challenging target of 340.
They were eventually all out for 264 to enable Worcestershire to end a frustrating run of four weather-affected Second Division draws in a row, although they were docked three points for a slow over rate.
Tony Frost frustrated Gloucestershire with his fourth first-class century as Warwickshire battled to ensure a draw was the only feasible outcome on a drab third day of the Second Division match at Gloucester's Archdeacon Meadow.
The 32-year-old wicketkeeper, brought out of retirement this season, ground out his ton off 237 balls, with 12 fours.
It enabled his side to reach 399 for eight in reply to 420 against a home attack deprived of injured captain Jon Lewis.
Frost went on to a career-best 141 not out, receiving good support from Jim Troughton (79), Neil Carter (24), Chris Woakes (26) and Naqqash Tahir (33 not out).Reuse content