Marouane Fellaini's quickfire red card provided the main talking point in an otherwise uneventful derby.
The Belgian was sent off late on for two bookings in 19 crazy seconds after he had clashed with firebrand City striker Sergio Aguero.
City had dominated possession and territory in the second half but, despite pinning United back, were unable to make their supremacy count.
David de Gea was largely untroubled with the hosts restricted to efforts from distance as the Reds mounted a brave rearguard action to earn a creditable point.
The result means the Premier League table is as-you-were with United a point behind City and two off third-place Liverpool, albeit with a game in hand.
The Reds lined up with a dynamic front three of Henrikh Mkhitaryan, Marcus Rashford and Anthony Martial, but it was City who came closest early on.
Kevin de Bruyne burst clear down the right and picked out Aguero who struck a post with his low, well struck effort.
The next clear cut chance went the way of the visitors as United almost took the lead in a strange manner on 25 minutes.
Claudio Bravo flapped at Martial's cross and the ball fell to the lurking Mkhitaryan but the much-criticised City stopper recovered well to block.
The ever dangerous Aguero went close from distance and de Gea saved well from Aleksandr Kolarov's ambitious 30-yarder shortly before the break.
The best chance of the half - and arguably the entire match - came at the other end in stoppage time.
Ander Herrera rose unmarked to meet Rashford's free-kick but the Spaniard could only head wide when well-placed eight yards out.
United spent the entire second half camped in City's half as Guardiola's side ratcheted up the pressure.
Raheem Sterling fired wide, Aguero headed over and Nicolas Otamendi went close with a deflected effort as the Reds hung on determinedly at the back.
Even the dullest of derbies provides a flashpoint, and this time was no different.
It came with six minutes to go as Fellaini was booked for a cynical foul on Aguero, before he was dismissed seconds later after a head-butt on the same player.
Yaya Toure went close as the clock ticked down and City substitute Gabriel Jesus headed in only to see the goal correctly flagged for offside.
Despite their numerical disadvantage and six added minutes, United held out in relative comfort to stretch our unbeaten league run to a 24th game.
Overall team performance: 7/10
United Faithful Man of the Match: Eric Bailly. Immense again.