Donaldson hit the one six and 12 fours while team-mate Arun Ramasamy also lifted one over the ropes before being caught just shy of his half century.
Ramsamy also hit five fours in the Borderer’s total of 195 all-out in the 45th over.
Hexham’s Rob Hook led their attack with 4-57, but Donaldson and Ramasamy proved difficult to dislodge from the crease with stands of almost two hours and an hour respectively.
Declan Mark and James Thompson then ripped into the Hexham batting as they took 4-17 and 4-22, decimating the Tynedalers to 83 all out in the 34th over.
Berwick host Allendale in Division Three of the NTCL this Saturday.
Tillside have dropped into the bottom two of the Second Division.
The Etal side have made a slow start and were beaten a home by four wickets by Bates Cottages.
They were all out for 125 in the 42nd over after electing to bat with and David Todd’s 27 and Rory McGregor’s 26 the top scores at the crease.
The visitor’s Elliot Ashburn bowled 3-15 and Liam Khan 3-32 as the wickets tumbled.
Cameron McGregor led the Tillside bowling with figures of 3-10 as Bates hit their winning target of 126 for 6 in the 35th over.
They travel to second-placed Cowgate Sports this weekend.