On-loan Everton striker Ellis Simms scored on his first start for Hearts as Motherwell were beaten 2-0 at Tynecastle.
Simms netted from close range in the 58th minute to double the lead as Robbie Neilson 's third-placed side moved 10 points clear of their nearest rivals in the cinch Premiership.
Andy Halliday had scored the opener in the 37th minute and Hearts could even afford to rest key attacker Barrie McKay for the majority of the game ahead of Tuesday's Edinburgh derby.
Motherwell had some decent first-half chances but Graham Alexander's team paid the price for losing the ball in dangerous situations before both goals.
The visitors survived an early scare when Stephen Kingsley had a shot blocked after an indirect free-kick just inside the box.
January signings Ross Tierney and Liam Shaw both made their first starts for Motherwell and both were involved as the visitors otherwise made a lively start.
Tierney was smart in possession and almost got on the end of Kevin Van Veen's return pass, while Shaw headed over from a decent opportunity.
Van Veen twice missed the target with Hearts on the back foot and Halliday had a header held by Liam Kelly at the other end.
Simms had some opportunities to show his pace in behind but Cammy Devlin put too much on a forward pass, and the loan striker then fell over after beating Kelly to a through ball before volleying high over from another chance.
Motherwell midfielder Barry Maguire went off injured after making a tackle and was replaced by Sean Goss, who was culpable for the opener three minutes later.
On-loan Celtic midfielder Shaw lost possession first inside his own half but Motherwell seemed to have averted the danger until Goss dwelled on the ball inside his box. Liam Boyce won it and Devlin rolled it for the unmarked Halliday to drill home.
Van Veen missed Motherwell's best chance late in the half when he sent a free header wide from six yards following a cross by former Hearts attacker Jordan Roberts.
John Souttar did not come back out for the second half after earlier picking up a knock in a collision with Callum Slattery. Toby Sibbick made his Hearts return following his latest move from Barnsley.
Hearts soon had chances to double their lead. Gary Mackay-Steven sent a weak effort straight at Kelly, who soon made a close-range block from Halliday.
The second goal came after Devlin won the ball off Shaw inside his own half and drove forward. The Australian fed Boyce, who played it across goal for Simms to tap in.
Hearts broke on Motherwell again but Boyce could not convert after rounding Kelly and an offside flag ended the attack.
Motherwell fans thought they might have had a penalty when substitute Peter Haring cynically tripped Slattery as the midfielder ran into the box but referee Craig Napier gave a free-kick. Roberts' effort hit the wall.
Craig Gordon ensured there was no late drama as he got down to hold Van Veen's long-range strike and got a hand to a fierce effort from substitute Justin Amaluzor.
