Mercedes is expected to make an announcement in the near future revealing who will partner Hamilton at the team next year, having spent the past few months deciding between Russell and Hamilton's current teammate, Valtteri Bottas.
Russell is widely expected to get the seat, having been part of Mercedes' junior programme since 2017 and starred during his time with Williams in F1 since debuting in 2019, as well as impressing in a one-off appearance for Mercedes in last year's Sakhir Grand Prix after Hamilton was sidelined by COVID-19.
Hamilton's former teammate Nico Rosberg, the 2016 F1 world champion, told Motorsport.com on Wednesday that he thought things could get "more heated" at Mercedes if Russell were to become Hamilton's teammate, posing a greater challenge than Bottas currently does.
Asked by Motorsport.com for his thoughts on how the potential move would change the team dynamic at Mercedes, Verstappen said he thought Spa runner-up Russell would "make it very difficult for Lewis".
"He jumped into the car in Bahrain, and basically he was already from lap one making it very difficult for Valtteri," Verstappen said.
"So you can only imagine the more experience you gain in that car, and the more you get accustomed within the team, naturally you're going to be becoming faster.
"When you do your first race, you are guided by the team about set-up direction, because you just don't know what to do really, initially, with the car. Even though of course F1 cars look pretty similar, the way of setting them up can be very different.
"So yeah, for sure, I'm very confident. Already what you could see, the performance he did in Spa was really good. Of course they set up the car a bit more for wet conditions, but nevertheless, to do that in a Williams was very impressive.
"I do expect him to do very well if he gets that seat."
Verstappen currently finds himself in a close battle with Hamilton for the F1 drivers' championship, sitting just three points behind after his half points victory at Spa last weekend.
The Red Bull driver will enter his home grand prix at Zandvoort this weekend looking to move back to the top of the standings for the first time since before the Hungarian Grand Prix.
It will be the first Dutch Grand Prix since 1985 after significant redevelopment of Zandvoort paved the way for the track's return to the calendar, capitalising on the fervent support for Verstappen.
"They've done an incredible job setting this all up, first of all hosting a grand prix, but also now how you look at the whole complex as a whole," said Verstappen.
"It looks very cool, and I hope we can have a good fun weekend.
"Of course you want good results, but I think that we can enjoy ourselves on Saturday once the fuel comes out and we can see how fast we can go around this track."