United bounced back from an early setback as Tam Courts enjoyed a 6-1 victory in his first home match in charge.
Kane Hester had already sent an overhead kick off the bar before giving the visitors the lead inside four minutes.
United quickly responded and pressure paid off when Lawrence Shankland netted from close range in the 19th minute, and the striker set up Nicky Clark to finish expertly five minutes later.
Shankland netted on the rebound in the 32nd minute after Clark had been denied and twice came close to his hat-trick before Peter Pawlett made it four five minutes from half-time when he chipped home.
Freeman fired home nine minutes after the break and then set up Mochrie to tap home 10 minutes later.
Steven Lawless scored his first Motherwell goal in 10 years as Graham Alexander's side edged past Queen's Park at Firhill.
Lawless, who re-signed for the club in January, squeezed home a finish in the 15th minute after a good burst into the box by Barry Maguire. The midfielder collected the rebound himself after forcing a save and back-heeled for Tony Watt to find Lawless.
Queen's Park gave Motherwell plenty of problems in the first hour though with former Fir Park youth player Liam Brown pulling the strings in midfield and Simon Murray posing numerous concerns.
Murray came close on a number of occasions while Tommy Robson and Callum Biggar also threatened. But Motherwell managed the game better in the final half hour and both Watt and Maguire threatened.
Arbroath bounced back from Callum Antell's red card midway through the second half to beat East Fife 2-0 at Gayfield.
With all substitutes used following Antell's dismissal for bringing down Ryan Wallace, midfielder David Gold had to take the gloves.
But Dale Hilson and Luke Donnelly netted in the final 20 minutes to earn the hosts the three points.