St Mirren have lost ground in their fight for Scottish Premiership survival after being held by St Johnstone.
Hearts' win over Hibernian, followed by Hamilton Academical's shock victory at Ibrox combined to leave Jim Goodwin's side just four points off bottom spot.
A Jon Obika effort hit the post in the first-half for St Mirren, while Jason Kerr headed against the bar late on for the visitors.
St Johnstone's Liam Craig was sent off with 10 to play for two yellow cards.
Tommy Wright's side are now unbeaten in six league matches, but lose ground in the race for a top-half finish.
Goodwin was bitterly disappointed following Saturday's Scottish Cup quarter-final exit to Aberdeen. It was not just his side's result which had him down. It was their failure to create clear-cut chances.
But he was not prepared to sacrifice defensive stability for attacking ability. In fact, he did the opposite, bringing in Ross Wallace as a holding midfielder for the more attacking-minded Cameron MacPherson.
It worked, insomuch as St Mirren were rock solid. Only Anthony Ralston really troubled Vaclav Hladky - a comfortable save for a goalkeeper of his quality - while Kerr's header was a brilliant effort. But the defensive discipline of both sides - until the last 10 minutes at least - ruined the match as a spectacle.
The opening stages had offered hope, with both sides opting for a direct approach in possession. There were a couple of last-ditch challenges, mazy dribbles, and almost a moment of pure brilliance from Obika to break the deadlock.
The striker swivelled to create half a yard before unleashing a left-footed effort which hit the inside of the far post and rolled along the line. Despite the lunge of strike partner Alex Jakubiak, the ball somehow stayed out.
That was about as good as it got for the next hour or so. Some quick St Johnstone play culminated in Ralston's effort, then Obika ghosted on to a Wallace free kick, but his composure was lacking and his effort was wayward.
It was becoming increasingly evident that something either exceptional or extraordinary was needed to earn all three points, and Jamie McGrath almost found the latter, as his cross missed everyone before bouncing off the woodwork and clear.
With the game labouring towards a conclusion, Craig made things interesting as he earned himself a second yellow card by bringing down substitute Tony Andreu. That finally kicked the game into life.
St Mirren poured forward and Obika thought he had won it, only for Clark to somehow tip his low strike wide. McGrath then was inches away with a long-range effort, but it was too little too late for the hosts.
St Johnstone are no slouches. They are now unbeaten in their last six league matches, while before this game, only Celtic had stopped them from scoring over the course of their last nine.
Ordinarily, it would be seen as a valuable point for the hosts. But this was no ordinary round of fixtures. With surprise wins for both Hearts and Hamilton, they are right in the middle of a relegation battle.
He missed a couple of chances, but Obika was comfortably St Mirren's biggest threat going forward.
He almost single-handedly engineered an opener and if Clark had not produced a save of the highest order, he would have won his side the game.
That's without a great deal of support from the rest of his team-mates. He has looked much-improved in recent weeks.
St Mirren manager Jim Goodwin: "St Johnstone are no mugs, I don't know why people would expect us to turn up here and roll them over. But of course we're disappointed not to take all three points.
"It's another game after Saturday that we haven't been able to score. Unfortunately we weren't able to come up with the solutions but on another night we may have just nicked it."
St Johnstone manager Tommy Wright: "I don't think either side deserved all three points. It was harsh on us to go down to 10 men but we battled away, we knew we would be put under pressure and it's another good point on the road."