Crosby had a goal and two assists after getting two goals and an assist in a 6-4 win against the Anaheim Ducks on Thursday.
Hornqvist is a grinding right wing who had 106 goals and 216 points in six seasons with the Nashville Predators. Playing with Crosby and Kunitz, his goals and assists per game are likely to rise.
"It's nice to play with Sid; he's the best player in the world," Hornqvist said. "I'm not going to change my game though. I'm still going to go hard to the net and create some space for my teammate. Obviously I couldn't ask for any better center."
Crosby is coming off a wrist injury that was tended to during the summer, and he looks every bit the player who won the Hart Trophy and Art Ross Trophy last season.
After a disappointing Stanley Cup Playoffs (one goal in 13 games), Crosby admitted it was crucial for him to get off to a good start, but added that's really no different than any other season.
"It's always important," Crosby said. "You come in with the mentality that you want to start quick and get some momentum and confidence. I had a long summer and a lot of time to think about last year and we're all pretty excited to get started. It's nice to see it translated into a couple of wins."
Hornqvist, asked what, exactly, Crosby does that is so special, said, "Sid is so strong on the puck and he can make things happen from nothing."
Toronto outshot Pittsburgh 4-1 in the early going, but the Penguins scored on their second shot of the game; Hornqvist beat goaltender Jonathan Bernier through the five-hole. Crosby and Kunitz also scored in the first period when the Penguins took a 3-0 lead before Maple Leafs forward Joffrey Lupul responded with his first of the season at 4:18 of the second.
Evgeni Malkin restored Pittsburgh's three-goal lead with his first of the season, a power-play goal at 13:46, and then Brandon Sutter of the Penguins and Tyler Bozak of the Maple Leafs traded goals in the third.
Toronto's top scorer from last season, Phil Kessel, is off to a slow start with no points and minus-2. In the third period, Kessel was demoted to the second line and replaced on the No. 1 unit of Bozak and left wing James van Riemsdyk by David Clarkson.
Maple Leafs coach Randy Carlyle pointed the finger at his top two lines, which are supposed to supply the team with offense, as the main reason they lost to the Penguins.
"When the tide of the game turned against our team so hard, we had no answer," Carlyle said. "You turn to your best players in that situation and they didn't have any answers."
The Maple Leafs, who lost their season opener 4-3 to the Montreal Canadiens on Wednesday, play at the New York Rangers on Sunday.