The Titans started the game brightly, leading 10-0 after the first five minutes. Right-winger Dan Leake crashed over in the fourth minute to score the first try of the game with full-back Alex Dolly having kicked an earlier penalty as well as the conversion.
Birmingham then hit back through hooker Adam Caves, who also scored twice later in the half as the hosts eked out an 18-16 lead at the break with Dolly kicking two further penalties for the Yorkshire side.
Man of the match Caves added a fourth try in the second half as Birmingham went 25-16 ahead, and although Dolly kicked two more penalties for Rotherham around the hour mark to narrow the gap to 25-22, there was to be no comeback with the Midlands outfit holding on for the win.
Trailing at half-time, Otley hit back to beat hosts and National Two (North) rivals Wharfedale 16-14 in a dramatic local derby.
Wharfedale edged the early exchanges with hooker Dan Stockdale running in under the posts in the 16th minute. Centre Oliver Goss touched down for Otley and scrum-half Joe Rowntree kicked a penalty to edge his side into the lead, but full-back Tom Mann scored and converted a try just before half-time to put the home side back in front 14-8.
Otley hit back with second row Brett Mitchell crashing over in the 51st minute, and they took the lead when Rowntree added another penalty in the 56th minute.
Elsewhere, Hull Ionians had to settle for a four-try bonus point as they were beaten 35-24 by hosts Hinckley.
Left-winger Sam Wilson’s 22nd-minute try was converted by centre Lewis Minikin before right-winger Toni Kuku added another just before the break – but Ionians were still 16-12 behind.
The Midlands outfit extended their lead with two further tries, and although the Yorkshire side hit back with centre James Tincknell and prop Ben Bell both scoring tries, it wasn’t enough.
Sheffield Tigers suffered a 24-18 home defeat to Chester in a nail-biting match which saw the lead change hands several times.
After an early unconverted Chester try, Tigers’ winger Greg Mellor touched down and stand-off Mark Ireland added the conversion and a penalty.
The visitors pulled level with another unconverted try, before winger Henri Packard touched down early in the second half to put Tigers 15-10 ahead.
A converted try on the hour mark put Chester ahead, but Ireland’s 64th-minute penalty edged the Yorkshire side back in front. However, a final try from Chester three minutes later sealed the win and left Tigers with just a losing bonus point.
Huddersfield were 26-15 winners at Macclesfield.
Harrogate were 33-29 winners over Wirral in the North Premier after surviving a comeback by their rivals.
Tries from flanker James Dyson (2), centre Nathan Wyman, and full-back Oli Rosillo helped Harrogate to a 26-3 lead as half-time approached.
Wirral hit back to 26-17 at the break and added more tries in the second half, but Harrogate held on with scrum-half Danny Matthews adding a further try.
Hull ran in nine tries on their way to a 55-12 win over Wilmslow, with Mike Adlard and Joe Stafford scoring two each.
Sandal ran out narrow 49-48 winners over Rossendale, while Ilkley lost 34-19 at Billingham.
Huddersfield YMCA beat Scarborough 29-26 in North One East, while Bridlington beat Cleckheaton 29-22.
Morley ran out 23-22 winners in their match at Pocklington, while Malton and Norton also won away by one point, beating hosts West Leeds 19-18.