McLaren went three rounds into 2023 before scoring a point as it struggled to find competitive form out of its car.
But a raft of upgrades brought for both Lando Norris and Oscar Piastri in recent races has allowed the former to score consecutive second-place finishes, while Piastri was in the top five for the past two races.
Albeit 136 points adrift of Mercedes in second in the constructors' standings, Russell believes McLaren is a genuine threat in the best of the rest fight behind runaway leaders Red Bull.
“It's absolutely clear they are true contenders for the second fastest team,” Russell said of the Woking outfit.
“It's very odd how Aston Martin were clearly that second best at the start of the year.
“And they don't seem to be so competitive right now. Ferrari haven't made much progress. And McLaren have made a huge jump.
“So if it wasn't for McLaren, we'd be very, very satisfied with the progress we're making. Moving ahead of the midfield pulling a gap on our rivals, closing on Red Bull.
“McLaren have just totally thrown it in the mix. But it gives you optimism that there is potential to make bigger steps.
“I believe in my team. I think it gives us confidence and optimism that we can make that step to Red Bull.
“We're not too focused really on McLaren or Aston or Ferrari. We're focused on Red Bull. And we're trying to make that big step.”
Source: Autosport