Bale is set to start for Real tonight as they face Atletico Madrid in the UEFA Super Cup in their first competitive match without Cristiano Ronaldo.
Ronaldo left the Bernabeu after nine years earlier this summer, joining Juventus on a four-year deal.
There was speculation during the summer over the future of Bale who was linked with a move to Manchester United.
But he stayed at Real Madrid and has now been backed to shine by Lopetegui, who is taking charge in his first competitive match after Zinedine Zidane left.
“We love that (Bale) is with us,” Lopetegui said.
“He is so motivated with a lot of hope and he’s been working well since the beginning of the season.
“We’re delighted with his attitude and his desire, he’s an ultra professional who is training with the desire of a youth teamer.
“We are convinced he will have a great season.”
Ronaldo moved to Juventus a few months after netting a stunning overhead kick in Turin in the Champions League, earning a standing ovation from the home crowd.
And the former Manchester United star recently revealed that the reception he got for his brilliant goal in April was a factor in deciding to move to Italy.
“I felt surprised at the beginning,” Ronaldo said in an interview with JuventusTV.
“I am used to following Juve and I like the club, but since that moment I liked them even more.
“I won’t say it was the key point in my decision, but every detail helps. Maybe. Of course, it helps when you see the people like you, the supporters and club like you, the feeling is completely different.
“Unbelievable. I remember every day, that never happened to me before. In the Champions League against Juve, a quarter-final, you score a goal and see everyone in the stadium applaud you. It was an unbelievable feeling.
“I don’t have a precise moment when I decided [to join]. During the years, we played a few times against Juve and I had a special feeling that the Italian supporters like Cristiano.”
Ronaldo will make his Serie A debut for Juventus on Saturday as the Old Lady travel to Chievo (5pm).