The club was charged on Tuesday for angry scenes that followed referee Mark Clattenburg's decision to award a penalty against Luke Shaw for a foul on Grant Holt.
Saints goalkeeper Artur Boruc kept out Holt's subsequent spot-kick but protests from visiting manager Mauricio Pochettino and his players continued after the final whistle of the 0-0 draw at Carrow Road.
The club had until 4pm on Friday to respond to the charge but they have accepted the £20,000 fine.


 





