Fresh from qualifying for the World Cup with New Zealand, Smeltz is still likely to be on a high when United travel to Adelaide for the round 15 clash at Hindmarsh Stadium but Rudan is hoping it's the opposite.
"He's a quality marksman," Rudan said. "I'm hoping that he's still having a few drinks after qualifying.
"I'm hoping he comes over with a hangover, that's what we're all hoping.
"But, in reality, it's not going to happen, he's professional enough to put that one past him."
Smeltz has netted on 11 occasions this term to be three clear of North Queensland's Robbie Fowler on top of the goalscoring list and Rudan knows it is no fluke that he is at the top echelon of strikers in the competition.
"He's not the top goalscorer for nothing," Rudan added.
"I remember when he first broke into the A-League a few years ago (2007 for Wellington), not all that many people knew about him.
"But he's one I marked down. He's very impressive with his movement and touches.
"Although he didn't score that day I faced him, I could just see that he had that something about him.
"Everybody knows who he is now."