The Claret Jug's probably nursing a pretty nasty syrupy hangover this morning -- 'cause Rory McIlroy filled it up with JAGERMEISTER after his British Open victory.
It appears Rory's mom was part of the raging after-party ... and stabilized the Jug while one of Rory's pals loaded it up with the Jager like it was a college sophomore in 2003.
Rory's victory drink was about $39,980 cheaper than Phil Mickelson's ... who recently said he filled the Jug with a $40k bottle of wine after he won the Open last year.
FYI -- seems Jager's his drink of choice ... Rory filled the U.S. Open trophy with the black sauce after winning that tourney back in 2011.
FILLS TROPHY WITH JAGER
... After Open Victory
7/21/2014 7:54 AM PDT BY TMZ STAFF
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