Motherwell, managed by Daly's former Stockport team-mate Jim Gannon, looked in control after recovering from Andy Webster's early opener at Fir Park to lead through goals from John Sutton and Lukas Jutkiewicz, but Daly levelled in the 83rd minute despite Prince Buaben's earlier red card.
Danny Swanson followed him down the tunnel in the 87th minute but Nicky Weaver earned United a point with a fabulous late save from Keith Lasley.
Daly had scored against Celtic last week in his first game since suffering a knee injury in April and again made an impact off the bench.
For Motherwell it was their third successive draw against opposition who had been reduced to fewer than 11 men.
The game burst into life in the 14th minute following a cagey opening spell when Webster took advantage of a soft clearance. Tom Hateley could only get the ball to the edge of the box as he intercepted a Paul Dixon cross and Webster chested it down and fired into the bottom corner.
Motherwell's response was instant though. They had a strong penalty claim rejected by Alan Muir when Dixon went to ground to halt Sutton after Jamie Murphy had played the striker in.
The ball broke to Jutkiewicz, whose volley was pushed wide by Weaver but Well converted the resulting corner.
Ross Forbes swung the ball out to the penalty spot and Sutton planted a firm header in the bottom corner.
The game continued to flow and Jutkiewicz's powerful long-range strike swerved wide.
United pressed and Danny Cadamarteri screwed a volley over following a long throw before John Ruddy pushed away Damian Casalinuovo's 25-yard strike.
But Jutkiewicz created a goal out of nothing to claim his sixth of the season in the 29th minute.
The on-loan Everton striker won himself some space 25 yards out on the left and fired a low shot across Weaver.
Muir dismissed penalty appeals when Jennison Myrie-Williams - booked moments earlier for a foul on Forbes - fell theatrically inside the box to the disgust of Ruddy.
Jutkiewicz then scuffed a volley wide from a half-chance and Ruddy held a low drive from Myrie-Williams at the second attempt.
Motherwell had the bulk of the early play in the second half but it was United who threatened.
Ruddy blocked Casalinuovo's shot from the inside-left position and Craig Conway drilled just wide from 20 yards.
Gannon brought on Keith Lasley and Jim O'Brien for Murphy and Forbes in the 57th minute but retained his midfield diamond shape, and United soon revamped their strikeforce with the introduction of David Goodwillie and Daly.
O'Brien was booked when Muir adjudged him to have dived just inside the United half but a foul on the Well sub earned Buaben a red card in the 67th minute.
Buaben had earlier been booked after reacting angrily when Muir penalised him for a challenge on Murphy and he was shown another yellow card for bringing down O'Brien in the centre circle.
Myrie-Williams escaped punishment after clattering into Steven Saunders and was replaced by Danny Swanson seconds later.
Jutkiewicz had the ball in the net in the 78th minute from Lasley's square ball but the substitute was ruled just offside from Giles Coke's pass.
Motherwell were keeping possession well but Ruddy came to their rescue after Lasley lost the ball in the centre circle. Swanson was sent clear down the left but Ruddy dived low to block his shot and Goodwillie put the rebound just over.
But United again broke down the left moments later through Dixon, whose low cross was sidefooted home by Daly.
Swanson was shown a straight red card in the 87th minute for a two-footed tackle on Lasley, the decision prompting United manager Craig Levein to come on to the pitch to protest.
Motherwell pressed but Weaver brilliantly pushed away Lasley's injury-time shot after a Yassin Moutaouakil cutback and Saunders headed the resulting corner over from inside the six-yard box.