The halfback, signed from NRL outfit St George-Illawarra Dragons, has added experience and quality to the struggling Londoners, since joining at the beginning of July.
“Jamie’s been great for us the last couple of weeks,” Robertson told Love Rugby League.
“He’s probably got one of the best kicking games in any competition in the world.
“That helps. He’s been good for us the last couple of weeks. His kicking game is second to none, really.
“He knows how to control a game, and he’s been in some pretty big games.”
Robertson insists, though, that Soward is not the only quality player at the Broncos’ disposal.
“We’ve got a couple of blokes who are like that though,” he added.
“We’ve got some experienced halves. They control the game really well.”