Hearts were held at home by Inverness CT on Saturday.
The visitors took the lead through Carl Tremarco but were pegged back by Arnaud Djoum’s second-half strike.
Ian Cathro made two changes to the side that drew against Hibs last week. In came Djoum, Perry Kitchen, Bjorn Johnsen and Choulay, while Sam Nicholson, Jamie Walker, Malaury Martin and Don Cowie missed out.
Isma was first to create an opportunity, showing quick feet in the ninth-minute to evade two ICT players before scooping his effort well over the crossbar.
He was in the thick of it again in the 22nd minute. Choulay’s corner was nodded down by Tasos Avlonitis and the Portuguese striker spun and hit it, but his net-bound shot was brilliantly blocked by Ross Draper.
The opening goal came two minutes later and it was for the visitors. Greg Tansey’s free-kick was met by the unmarked Tremarco, who steered his header beyond Jack Hamilton and into the back of the net.
On the half-hour mark Hearts were denied by the crossbar. Kitchen drove into the box before finding Johnsen, who took a touch before his shot was deflected up and off the woodwork.
A long-range screamer from Andraz Struna had Fon Williams backtracking, and the Caley ‘keeper managed to touch the ball over the bar.
From the resultant corner, Choulay found Isma, but the striker could only head wide.
Hearts attacked straight from the off in the second-half. Johnsen’s low cross was backheeled by Isma into the path of Kitchen, but he could only stab wide.
Johnsen was an early second-half casualty, making way for Walker, who made his 150th appearance in a Hearts shirt.
The Jambos were again denied by the woodwork, this time after 51 minutes. Choulay’s looping cross into the box was hit first-time by Isma but the ball agonsingly spun off Fon Williams’ right-hand post and clear.
That equalising goal was finally found in the 64th minute. Kitchen received the ball 20-yards out from goal by Lennard Sowah, and his cross to the back post saw Djoum burst forward to slam beyond Fon Williams.
Substitute Rory Currie did well to create space for himself inside the box after receiving the ball from Walker, but his shot was straight at Fon Williams.
Hearts had the woodwork to thank for keeping the scores level in the 74th minute. Aaron Doran’s deep corner was headed goalward by Draper and the ball somehow bounced across the six-yard box and off the post.
A minute later Hearts were handed the perfect opportunity to take the lead, when Draper bundled over Isma inside the box. Walker stepped up but Fon Williams threw himself across his goal to touch the ball away.
From the corner that followed, Walker plucked the ball out of the air to hit a sweet first-time volley from 18-yards, but an outstretched Caley Thistle leg cleared just as the ball looked to be sneaking into the bottom corner.
The Jambos went close again when substitute Martin’s corner found Alex Tziolis, and his deft flick goalwards flew inched over the bar.
Space opened up for Martin to hit a 20-yard drive but it was comfortable for Fon Williams, as time began to run out to find a winner.
Despite five minutes of injury time that second goal proved elusive and focus now turns to Wednesday's Edinburgh derby.
Hearts: Hamilton, Struna, Hughes, Avlonitis, Sowah, Kitchen (Martin, 76'), Tziolis, Djoum, Choulay (Currie, 62'), Johnsen (Walker, 49'), Isma. Subs: Noring, Nicholson, Nowak, Smith.
Inverness CT: Fon Williams, Raven, Tremarco, Polworth, Draper, McCart, McKay (Anier, 80'), Mulraney (Doran, 62'), Tansey, laing, Cole. Subs: Hoban, Ebbe, Fisher, Boden, Gilchrist.
Referee: Bobby Madden
Top Man: Alex Tziolis