Ross Forbes struck the top of the crossbar after 75 minutes as Well were second best in the stalemate but still confirmed their place in the top half of the table after Inverness drew 1-1 at Kilmarnock.
Hearts had the better of territory and possession, but struggled to break down a stubborn visiting defence and now have one win in six games.
While Hearts' bid to wrap up third place continues to stutter, Well have an unassailable seven-point lead over Caley Thistle after playing their final match before the SPL split.
Stuart McCall's men began the day with a seven-point advantage over Inverness, who have two games in hand.
But with next week's Scottish Cup semi-final with St Johnstone in mind, McCall named Jamie Murphy, John Sutton and Keith Lasley only on the bench.
The visitors were second best for much of the first half, but did enough to frustrate Hearts and could have gone in front themselves.
After two early Hearts corners came to nothing, Steve Jones flashed a shot over from the left of the area after a mix-up between Jason Thomson and Ismael Bouzid.
Stephen Elliott's effort from Skacel's cross went over at the other end before Hearts called Motherwell goalkeeper Darren Randolph into action.
After Jason Thomson's cross was half cleared, Ryan Stevenson's low shot across goal from the right edge of the area was palmed away by Randolph.
Hearts did not test the Well stopper again before the interval, but their own goalkeeper was called into action.
Jason Thomson gifted the ball to Esteban Casagolda on the left.
The striker went to ground on the edge of the Hearts area and the ball ran for Steve Saunders to shoot from 20 yards, Jamie MacDonald making the save to his right.
Saunders was replaced by Steve Hammell at half-time.
Maurice Ross, who switched to right back to accommodate Hammell, was booked for a lunge on David Templeton on halfway, the Hearts winger having already turned him.
Randolph saved from Templeton's jinking run and blocked a rebound attempt as the hosts resumed on the attack.
Tom Hateley's direct run took him past three Hearts defenders, but he lost control of the ball just as he entered the box and MacDonald collected.
Motherwell were coming more and more into the game and Jason Thomson was fortunate not to be penalised for a clumsy challenge on Steve Jones at the by-line but the ball had already drifted out of play.
Hearts made three changes in the 61st minute, with Ian Black replaced by Driver, Templeton by Suso Santana and Scott Robinson coming on for Elliott.
Robinson had a shot blocked before Santana shot over as Hearts continued to struggle to test Randolph.
Skacel shot narrowly wide from 25 yards before Motherwell introduced Sutton.
The striker headed a long ball on for Forbes, who struck a volley which hit the top of the crossbar.
Jason Thomson was then booked for bringing down Chris Humphrey, with the Motherwell winger launching a counter attack.
Humphrey was brought off for Murphy soon after.
Murphy was immediately in the thick of the action and drew a foul out of Bouzid, who was cautioned for the challenge.
Craig Thomson's free-kick from wide on the left was clawed clear by Randolph with five minutes remaining before Motherwell again went close.
Forbes' left-foot effort from 25 yards went narrowly wide at the other end before Bouzid did just enough to prevent Sutton getting in a shot on the turn.
Despite finishing the match the better, Well had to be content with a point and their place in the top half of the table was confirmed by the draw at Rugby Park.