Bale is set to make his second Spurs start since returning to the club in Thursday's Europa League match in Belgium, having made his full debut against LASK last week before being an unused substitution in the win at Burnley on Monday.
The 31-year-old arrived at Spurs in mid-September on a season-long loan from Real Madrid with an injury and short of match-fitness, having barely featured for the Spanish giants for 18 months, but Mourinho says his training data suggests Bale is now close to peak condition.
"Bale is playing," Mourinho said in Antwerp. "We all have, not just the feeling, but also the data that Bale is arriving. He is working very hard. He is being quite a great example for everybody.
"A big guy like him, travelled to Burnley, stayed on the bench for 90 minutes, didn’t play one minute. His behaviour as a team guy is incredible. His behaviour as a Tottenham man is remarkable and he is coming.
"I can see just with my eyes but then the scientific data is also coming and he is working very, very well. He is improving, he is improving a lot and I think tomorrow we can see Gareth at a good level and hopefully he can fly because he is working very hard."
After leaving Spurs for a world-record fee in 2013, Bale helped Real to four Champions League titles in five years, scoring in two of the finals, and multiple other trophies.
His time in the Spanish capital ended in acrimony, however, after his relationship with the Real fans, head-coach Zinedine Zidane and the Spanish media broken down irreparably.
"One thing is [his] reputation [in Madrid], another thing is facts," said Mourinho, who managed Real between 2010 and 2013. "I would love to have his reputation and four Champions Leagues. I have only two.
"The facts with Gareth are that he made a difference at that club. It was a club for years and years and years and years, more than one decade without even a quarter-final of a Champions League, then a big jump in front with three consecutive Champions League semi-finals and when he arrived, they won four in five.
"For me, these are the facts. The reputation is not important for me. The facts are important. He made a huge difference in the club.
"I can only speak about him with us. And him with us: amazing. Of course, he arrived injured. Of course, when you are injured for such a long time, it takes a little bit of time.
"We are giving him that time. He is working very hard. I think he is very pleased with the level of organisation we have in the club. Probably, he is not used to it. But the way we work between coaching staff, medical staff, sports science area, we are providing all the best conditions for his evolution.
"He was on the bench, he played some minutes, he started a match, he was on the bench, he is starting tomorrow again and we are giving him time. But again I repeat what I told before: he is in a better place than he was a couple of weeks ago. He is arriving."
Mourinho will be without Tanguy Ndombele and Eric Dier against Antwerp, with the duo having been left in London as a precuation, while Japhet Tanganga remains sidelined with a thigh problem and Paulo Gazzaniga, Joe Rodon and Gedson Fernandes are ineligible.
Serge Aurier and Steven Bergwijn are available after missing the 1-0 win at Turf Moor with knocks.