However, Gidley set up a grandstand finish with an individual try in the 70th minute.
The Knights had a number of chances in the closing stages to steal the win but the Bulldogs hung on, extending their winning streak to four and keeping their top-four hopes alive.
Newcastle's Tariq Sims opened the scoring when he followed a 12th-minute Gidley chip towards the corner that was overrun by both Nathan Ross and Brett Morris.
Gidley's sideline conversion was met with a roar from the crowd of 23,604.
The Knights looked certain to double their advantage on a right-side shift not long after, however Curtis Rona intercepted on the final pass and raced 95 metres to score.
In a high-octane first half, the visitors took the lead when Hodkinson found Lafai and was felled in the same motion by Sims in the 25th.
Then Damien Cook showed serious speed to burn speedster Mamo on a 45-metre run from dummy-half in the 32nd minute to give his side a 14-6 lead at the break.
The hosts kept in touch with the Bulldogs when Ross chased down a Tyrone Roberts grubber in the 52nd, before Pritchard went over for what turned out to be the match-winning try.
- AAP