Danny Phillips scrambled home from a corner to put the hosts in front four minutes before half-time amid driving wind and rain at the Bypass Ground.
And with seven minutes remaining, Gajic popped up with a glancing header from an inswinging corner which flew inside Brad Snelling’s far post.
Arnold told the Daily Echo: “The conditions dictated and a draw was a fair result. We deserved something from the game.
“Romsey played the conditions better than we did because we tried to play football in the wrong areas. You have to adapt your game in situations like that.
“It was vital we got something from it. They really needed to beat us and, having been 1-0 down at half-time with the conditions as they were, I was happy with the draw.”
Potters: Lynch, Evans, Molyneaux, (Joy, 68), Thoroughgood, Kelly, Dancer (Satterley, 56), Gajic, Oldring, Lovell, Saxby (Rutten, 81), Dyer. Unused subs: Hill, Murray.
- Christchurch’s trip to Totton & Eling in Wessex Premier was postponed.