It took Tonali only six minutes of his maiden league appearance to score his first goal for the club, setting Newcastle on their way to a 5-1 win over Aston Villa.
"He was magnificent. The goal, sometimes these things are just meant to happen, and he's arrived in the box and it’s a great finish," Howe told Newcastle's official website.
"I'm delighted with his overall performance. He knitted into the midfield very well. He's built a really good relationship with Bruno [Guimaraes] and the players on the right-hand side. You can see how good he can be."
Howe was also happy to see another debutant, Harvey Barnes, make an immediate impact with a goal and an assist as a substitute.
"The game was perfectly set up for him," Howe said. "Their line was high and fresh legs made a difference. He combined really well with Callum [Wilson] for one goal and it was great to see Harvey run through and score himself."
Howe revealed that he and his players targeted an opening-weekend win due to the toughness of their early schedule, having to face Manchester City, Liverpool and Brighton & Hove Albion in their next three matches.
"It was a massive win for us," he added. "When the fixture list came out we knew the importance of this game, a home game, with Manchester City and Liverpool to come. It was an electric start. The crowd were amazing."
Now Howe is targeting a statement win at the reigning champions next Saturday, claiming today's win over Villa was far from the best his side can be.
"We weren’t perfect today," Howe said. "There’s a lot we can improve. Defensively there were a couple of scary moments. We’ll go back and find little tweaks to make us better.
"Manchester City is the toughest place to play in the Premier League. But we go there feeling good about ourselves. We're prepared to try and win."