The East Yorkshire outfit opened their campaign with an impressive 19-0 win at Huddersfield, while Warrington won 22-8 at home to Salford.
“I’m expecting a fast, physical game against Hull,” said Penny.
“They’ve made some new signings and they’ve got a new half-back combination. They’ve got some big players, and some fast players as well.
“They’re a good threat and we’re looking forward to the challenge.
“I think if you look at the table at the minute, it’s the two best defences after one game.
“They managed to nil a good side in Huddersfield last week, and no matter what game you’re playing in, to nil a team in 80 minutes is a massive achievement, so they’ll be flying high with confidence.
“But we’re certainly confident we can go there and get the win on Friday.”
Penny is enjoying being in the first team at Warrington after rejoining the club last year. While his appearances in 2014 were limited by injury, he is relishing challenging for a first-team spot once again at the Wolves.
“We’ve got a great squad of players here,” he said.
“We’ve got a lot of versatile players who can play anywhere. I think we’ve got four wingers in the squad, so you can’t afford to get too comfortable or too relaxed in this team.
“You’ve got to be performing, and not just each week on game day, but in training as well.”