Clanfield conceded twice in the last six minutes to lose 2-1 at home to Tuffley Rovers in Uhlsport Hellenic League Division 1 West.
All the action came late on, with Jack Allan opening the scoring for the hosts in the 75th minute.
But Clanfield were unable to close the gap on the top three as they stumbled late on.
Tuffley equalised through a Shayne Bradley penalty in the 84th minute and Junior Mbika grabbed the winner a minute from time.
In Division 2 West, Old Woodstock Town crashed to an 8-0 defeat at Cirencester Town Development.