Leaders Exeter Chiefs ended Saracens' unbeaten 19-match home Premiership run by grinding out a 20-18 victory in a keenly contested top-of-the-table clash.
Having lost to Gloucester last time out and been beaten by the Chiefs in last season's semi-final, Sarries were keen to make a statement at Allianz Park - where they had not lost in the league since March 2016 - against the defending champions.
And the hosts made a great start when Alex Goode responded to Gareth Steenson's early penalty by diving over after seven minutes, before Schalk Brits dotted down while Nic White was in the sin-bin.
However, another Steenson penalty kept the Chiefs within striking distance and Ian Whitten broke the hosts' defensive line five minutes after the interval to further reduce the arrears.
A monster penalty from Marcelo Bosch stretched the home side's lead, but Moray Low touched down at the end of some brilliant work from Exeter's forwards and Steenson added what proved to be the winning extras.
In Sunday's other fixture, Wasps survived a huge scare to win 17-13 at bottom club London Irish.
Irish led 10-0 thanks to Alex Lewington's score and the boot of Tommy Bell.
But tries from Ashley Johnson, Josh Bassett and Nizaam Carr helped Wasps to a narrow comeback win.