Bucks County Cricket were knocked off the top of the Eastern Division in the Unicorns Counties Championship after a 143-run defeat away at Northumberland.
After three successful run chases had taken them to the top, Bucks this time collapsed on the final day and have now dropped to third in the table.
Bucks had inserted their opponents into bat on the first day, and the home side rattled up 429-8 from 90 overs despite excellent bowling from Dan Hampton, who returned fine figures of 5-93 on a fast-scoring ground.
Bucks seemed set to match that total when Shaan Khan (77) and Charlie MacDonell (92) put on 153 for the first wicket in reply. But a mid-innings collapse, which saw Bucks lose five wickets for 10 runs, led to them declaring on 340-9, 89 behind.
Three quick wickets for Sam Helm gave Bucks hope in the Northumberland second innings, but they recovered to 272-8 dec, setting Bucks a victory target of 362.
Bucks were given another good start of 95 by Khan (60) and Macdonell (63), but there followed another collapse and only a fine 55 from George Russell enabled the visitors to reach 218 all out.
Bucks will try to get back to winning ways when they play Lincolnshire at Tring Park on Sunday August 2.