Substitute Josh Coley struck a stoppage-time equaliser as Sutton fought back to draw 1-1 at Tamworth in their opening Vanarama National League match.
United – relegated from the EFL at the end of last season – had an early chance when Dillon De Silva sent a shot wide.
National League North champions Tamworth went close when Daniel Creaney headed over from a corner and then midfielder Ben Acquaye saw a long-range effort drop just off target.
The hosts thought they had won it when Nathan Tshikuna fired in a low strike with just six minutes left, only for Coley to thump in a late volley and secure Sutton a point.
