Walsall, unbeaten in 13 games, edged a point closer to the League One play-off zone, despite being held at home by promotion rivals Sheffield United.
Craig Westcarr fired home his fifth goal in eight games from inside the box to put Dean Smith's Saddlers ahead two minutes before the break.
But Kevin McDonald set up substitute Chris Porter's 65th-minute equaliser.
It was the first goal conceded by Walsall keeper Sam Johnstone in four starts on loan from Manchester United.
Walsall, really needing a win to not only boost their play-off hopes but also mark their 125th anniversary celebrations, dominated the first half.
Despite still being without injured top scorer Will Grigg, the Saddlers poured forward repeatedly, dangerman Febian Brandy shooting wide after he broke clear to create a chance for himself on 42 minutes.
But Walsall took a deserved lead two minutes later when Ben Purkiss combined with James Baxendale, who crossed low for Westcarr to beat George Long with a low shot.
Brandy missed a great chance to seal it for the Saddlers when he shot wide in the 51st minute with only the keeper to beat.
But Blades boss Danny Wilson had made two key substitutions at the start of the second half and one of the newcomers, Porter, grabbed the equaliser from close range after McDonald's shot had come back off a post - his first goal since returning from loan at Shrewsbury.
VIEW FROM THE DRESSING ROOM
Walsall manager Dean Smith told BBC WM:
"On chances, we deserved to win. For an hour to today we we outstanding against one of the best sides in the league.
"On another day Fabien Brandy will score two or three. All the chances seemed to fall to him and he's normally clinical.
"They got back in the game with a goal and, in the last 20 minutes, they put us under pressure, but we still had chances.
"The dressing room is a bit disappointed, but 13 games without defeat is not to be scoffed at in this league."
Blades manager Danny Wilson told BBC Radio Sheffield:
"I think in the first half we were second best and we got away with it in terms of the scoreline.
"To lose a goal virtually on half-time was a real setback.
"Second half was quite the opposite. We've taken the game to them, got the goal and we look like we could go on and win the game.
"It wasn't to be, so I can't be too critical and it possibly was a fair result."