The gap between the clubs is fully nine points now and after their sixth away win of the campaign, Well will feel confident that they can do it again at Tynecastle in next month's Scottish Cup fourth round meeting.
Hearts made five changes for this game, welcoming back midfielder Michael Stewart from suspension, while losing Laryea Kingston to injury.
Top scorer Andrius Velicka was also promoted to the starting line-up following his late penalty equaliser against Celtic and the burly Lithuanian soon created Hearts' opening goal with a first-time cross from the right, which Andrew Driver volleyed left-footed into the far corner.
Driver had already fired an early sighter over as did Motherwell's Ross McCormack, but Hearts were not threatening to dominate and full-back Robbie Neilson wasn't far away with an angled right-foot effort.
On the half hour mark Andrius Ksanavicius set up Velicka with a subtle little pass and keeper Graeme Smith did brilliantly to block Velicka's chipped finish.
Four minutes later Hearts goalkeeper Eduardas Kurskis - on his debut - made an astonishing reflex stop after Zaliukas had deflected the ball towards his own net.
Motherwell upped the pace at the start of the second half and after McCormack had clipped the crossbar with a free-kick and then shot narrowly wide from 30 yards, the visitors deservedly drew level.
Hearts fell asleep at a quickly taken corner and David Clarkson pulled the ball back from Jim Paterson's deep cross for Chris Porter to head home from point-blank range.
As if having to battle against driving snow and rain wasn't difficult enough it then got even worse for Hearts when Motherwell edged in front midway through the second period.
This time Steven McGarry crossed from the right and when McCormack headed the ball back into the danger zone, Zaliukas stabbed it past Kurskis for an own goal.
By now playing conditions were almost impossible and although Eggert Jonsson and skipper Christophe Berra both went close from long range, the Edinburgh side failed to repeat last weekend's injury-time equaliser against Celtic.