Anthony Gordon's penalty put Newcastle in front, but the hosts were already down to ten men and Casemiro levelled with virtually the last kick of the half.
The Magpies started with real purpose and a Kieran Trippier cross-cum shot clipped a post at the Leazes End inside the opening four minutes.
Then a wonderful move from the Magpies ended in Casemiro blocking a shot from Harvey Barnes.
In the 13th minute, Anthony Elanga - who started his professional career with Manchester United - volleyed narrowly wide. And after Joelinton dispossessed Kobbie Mainoo in his own box, Barnes curled an effort just off target a minute later.
Sandro Tonali was next to threaten, sending a low drive just the wrong side of goal in the 20th minute.
The likes of Tonali, Joelinton and Jacob Ramsey were routinely winning the ball from red shirts - albeit they were sometimes guilty of surrendering possession rather cheaply too - and another swift Newcastle break, from Anthony Elanga to Gordon to the galloping Joelinton, resulted in the Brazilian advancing dangerously but firing over the top.
Shortly before the break, Elanga got to the byline and cut the ball back for Barnes, who attempted to flick beyond Senne Lammens but the Belgian goalkeeper was able to gather.
At the other end, Aaron Ramsdale's first save of the night was a brilliant one as he flew across his goal but push away an arcing shot from Mainoo, with the ball seemingly destined for the top corner of the Gallowgate End net.
Then Ramsdale pushed away a stinger from Matheus Cunha, who had got the wrong side of Kieran Trippier. Bryan Mbeumo blazed over from the rebound.
Ramsdale had replaced Nick Pope in goal while Barnes also came into the starting XI in the other change from Saturday's defeat to Everton. Nick Woltemade missed out through illness.
But in first-half stoppage time, Ramsey was shown a second yellow card for what, in referee Peter Bankes' view, was simulation as he tried to round Lammens. He'd earlier been booked for a tug on Casemiro.
Newcastle, though, kept pushing and Gordon had his heels clipped by Noussair Mazraoui in the box. This time, Bankes pointed to the spot - and Gordon converted coolly.
Casemiro, however, headed a Bruno Fernandes beyond Ramsdale deep into stoppage time to restore parity.
**Newcastle United:** Aaron Ramsdale, Kieran Trippier (c), Lewis Hall, Joelinton, Sandro Tonali, Anthony Gordon, Harvey Barnes, Malick Thiaw, Anthony Elanga, Dan Burn, Jacob Ramsey
**Subs not used:** Nick Pope, Sven Botman, Yoane Wissa, William Osula, Jacob Murphy, Joe Willock, Alex Murphy, Leo Shahar, Sean Neave