Jackie McNamara's side savaged Airdrie United 7-0 to move two points clear as rivals Dunfermline Athletic dropped two points at home to Morton.
There was little doubt where the points would go at Firhill from the moment Chris Erskine struck the first blow three minutes in.
He won a penalty shortly after for Aaron Muirhead to convert and, by half-time, Partick had extended the margin to 5-0, Steven Lawless adding the third, Sean Welsh scoring a fourth and Erskine number five.
Substitute Kris Doolan added to Airdrie's misery with a lob over Kenny Arthur before sub Scott Sally was sent off for Airdrie for dangerous play.
Ross Forbes completed the scoring with a speculative effort from the right. Airdrie have now conceded 11 goals in two games.
At East End Park, Dunfermline fought back from two down to get a 2-2 draw against a Morton side who won their last five games.
Archie Campbell scored twice for Morton to put them in a strong position with ten minutes left.
But the home side scored twice, a Stephen Husband penalty after hand-ball by Mark McLaughlin, and a Ryan Wallace header.
Raith Rovers were even more dramatic in their 4-4 draw at Cowdenbeath, twice coming back from two goals down.
Kyle Miller gave the home side an early lead after David McGurn had saved from Greg Stewart, and Jamie Stevenson doubled their advantage with a distant free-kick.
Brian Graham scored his 13th of the season to pull a goal back after a free-kick and Greig Spence headed an equaliser before half-time.
Substitute Lewis Coult headed home then scored his second with ten minutes left to make it 4-2 before Pat Clarke pulled a goal back and Simon Mensing got an injury-time equaliser.
Falkirk claimed only their second league win of the campaign with a 2-0 win at bottom club Dumbarton.
Lyle Taylor gave them the lead after Scott Agnew was caught in possession, and David Weatherston scored a second.
Livingston held off Hamilton Academical 2-1, with all of the goals in the first ten minutes. Steve May gave Hamilton the lead in the first minute. Stefan Scougall equalised and Marc McNulty produced a fine finish to put Livingston ahead.
Alex Neil was sent off for Hamilton for a bad challenge with 20 minutes left. Four minutes later Livingston's Kevin McCann joined him after two bookings.
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