At a Glance
The Red Devils' poor recent struggles continued at Elland Road, but head coach Ruben Amorim had his Brazilian forward to thank for the team not suffering even more disappointment against their old rivals.
The Everton loanee headed a first-period attempt against the post for the in-form hosts before Brenden Aaronson finished superbly with a driven, 62nd-minute effort.
With the goal, the United boss was in the firing line after his side had been held by struggling Wolverhampton Wanderers at home earlier in the week.
However, against opponents who had two days less to prepare, Cunha restored parity three minutes after the opener when he latched onto a through ball from introduced Joshua Zirkzee and guided a finish underneath rushing Leeds goalkeeper Lucas Perri.
It was only the Brazilian's fourth goal since his high-profile summer move and came at a time when the manager is without several key attacking players due to a combination of fitness issues and national team commitments.
Not that you would expect the hosts to sympathise with that given their own tight schedule.
Noah Okafor forced a diving save out of Manchester United goalkeeper Senne Lammens with a audacious overhead kick, and United heads were in hands when Benjamin Sesko, who is struggling to make an impact, turned Zirkzee's cut-back wide from close range.
The goalscorer, who had a goal disallowed for offside much earlier in the contest, also blasted against a post in the dying moments.
The draw extends Leeds' unbeaten run to seven games, their best such streak since over two decades ago, and takes them a significant margin clear of the drop zone.
For the visitors though, it was yet another chance to move into the Champions League places, albeit only for a matter of hours, squandered.
With the Africa Cup of Nations reaching its latter stages, Amorim could be understood for hoping the involved countries make a swift exit.
Existing injuries to skipper Bruno Fernandes and Three Lions star Mason Mount only exacerbated the impact the absence of other attackers is having on Amorim's squad.
It's not that the absent players are the solution to all of the club's problems. After all, they were part of the side that suffered poor results earlier in the season.
But without them, the boss has limited alternatives in attack.
He clearly does not have full faith in youngster Shea Lacey or the much more experienced Zirkzee, even though the Dutch forward delivered the assist for Cunha's equaliser almost instantly after his arrival as a substitute.
That leaves Cunha, who has now scored three goals in recent outings, and others playing out of their natural positions, alongside Sesko.
On this showing, the big-money frontman looks no better than previous underwhelming signings, lacking in confidence and conviction in front of goal.
His failure to turn home Zirkzee's cross means it is now a long run without a goal for the young striker.
After thrilling victories in their previous home games, the arrival of their biggest rivals to Elland Road was a comparatively subdued affair.
True, there were instances of typical fervor, but the hostile edge was not as evident as in other fixtures.
Leeds' fans were more preoccupied about their side's inability to get sustained possession in advanced areas for any length of time.
The Calvert-Lewin header that struck the post was an isolated moment of threat in a congested first half.
It still felt as though the hosts were struggling when a defensive error opened the door for Aaronson.
For a short moment, Leeds' ecstatic fans thought they were about to secure a rare win against Manchester United.
However, there is a much bigger picture for the manager and the club to deal with.
When they suffered a difficult run of form earlier in the campaign, many speculated about the manager's position.
In contrast, he is now masterminding significant progress.
The task is not done yet but step by step, the team are getting closer to achieving their top-flight status.
Leeds have a top-flight trip to St James' Park in midweek, followed by the start of their domestic cup campaign next weekend. Manchester United face a Premier League trip to Burnley before also entering their cup journey with a home tie.
A tech journalist with over a decade of experience covering UK innovations and consumer electronics trends.