Defeats at the top and bottom
Thatcham restricted the home side to a modest 140 all out with Scott Gibson taking 5-30.
But Waqar Ahmed improved on those figures, ripping through the Thatcham order to take 8-43 as the visitors were shot out for 82 inside 32 overs.
The result took Burnham back to the top of the table while Thatcham slipped to fourth, 23 points adrift.
Newbury also came unstuck at second in the table Chesham, where they slid to defeat by 143 runs.
bowled well but the experienced Aftab Habib and Andy Goddard stuck it out for 30 overs with Habib eventually run out for 78 and Goddard making 46.
Barney Atkins added an unbeaten 55 and Ollie Turner 20 not out as the Newbury bowlers tired and the home side posted 211-4 in their 52 overs.
Newbury were in trouble when skipper Charlie Anstey was clean bowled by Matthew Rance’s first delivery of the innings and he went on to take 4-25 with Tom Turner snapping up 4-17.
Only Rajeev Hanabe reached double figures with 15 while Ed Uden batted doggedly to score nine in the innings’ longest stay before Newbury were dismissed for 68 in the 36th over.