Partick Thistle defeated Ross County 2-0 in the first leg of the cinch Premiership play-off in front of more than 7,000 fans at Firhill on Thursday night.
Superb first-half goals from Aidan Fitzpatrick and Brian Graham made the difference against a County side who had defender Dylan Smith sent off.
The second leg takes place in Dingwall on Sunday, live on Sky Sports at 4.30pm.
