Alexandros Tziolis capped his full debut with a goal and Esmael Goncalves scored twice as Hearts won their second game in succession after beating Motherwell 3-0 at Fir Park.
Hearts dominated first-half possession but Motherwell created the better chances with Lewis Moult's header rattling the bar, before Lionel Ainsworth's effort was cleared off the line by Anastasios Avlonitis.
The game turned in the 53rd minute when Motherwell's Carl McHugh was sent off for a wild lunge on Hearts midfielder Don Cowie.
And six minutes later Greece international Tziolis netted with a speculative effort, which looped over Motherwell goalkeeper Craig Samson after taking a wicked deflection.
Fellow January signing Goncalves rounded off the win in style with two goals in four minutes late on.
On-loan Stoke winger Choulay was the provider for both as Goncalves curled past Samson in the 84th minute before drilling past the Motherwell stopper two minutes from time.
Aberdeen went second in the Scottish Premiership after a 2-0 win against Partick Thistle at Pittodrie.
Substitute Jayden Stockley got on the end of a 72nd-minute Niall McGinn corner to put the home side ahead before Ryan Christie opened his Dons account with Aberdeen's second in added-time.
Rangers now trail Aberdeen - who also have a game in hand - on goal difference after being held to a 1-1 draw at home to Ross County.
County took a surprise 18th minute lead at Ibrox before Rangers levelled through skipper Lee Wallace in the second half.
Kilmarnock moved up one place to eighth in the Premiership after earning a 1-1 draw against Hamilton Academical at New Douglas Park.
Sean Longstaff put Kilmarnock ahead with a clinical strike on seven minutes before Daniel Redmond equalised for the home side two minutes shy of half-time.
And Inverness Caledonian Thistle remain bottom of the table despite coming back from two-down to claim a share of the points at home in a 2-2 draw to Dundee.
Marcus Haber and Darren O'Dea scored in the space of six first-half minutes to give the visitors a two-goal cushion at the interval.
But a Billy McKay penalty and a Greg Tansey leveller 11 minutes from time earned the home side a point at the Caledonian stadium.