Gatland takes charge of his 117th Wales Test in Saturday's World Cup warm-up clash against Ireland.
A Dublin return follows next weekend before Wales head to the World Cup in Japan, after which Gatland will end a 12-year tenure.
Cardiff Blues back-row forward Navidi captains Wales for the first time this weekend, and he readily acknowledges Gatland's impact that is highlighted by three Six Nations Grand Slams and World Cup semi-final appearance.
"He has been massive - what he has achieved has been huge," Navidi said.
"He's been a big part of rugby, and what he has brought to Welsh rugby is second to none.
"Hopefully, we give him a nice home send-off and then can concentrate on the World Cup."
Gatland's priority is the game on Saturday and then selecting his 31-man World Cup squad, but he is certain to receive a rapturous Principality Stadium send-off.
"It will be quite emotional," Gatland said. "I've had an unbelievable time here in Wales, the people have made my time incredibly special.
"I'm trying to keep it in perspective. It's something I will be thinking about, but it's not about me.
"I will just have a personal reflection and look back on how memorable it's been, without making a big fuss about it."
Gatland has made 14 changes from the side that accounted for England a fortnight ago, with only Scarlets flanker James Davies remaining.
And there are a number of players with a chance to stake final World Cup selection claims ahead of Gatland's Sunday squad announcement.
Wing Owen Lane and prop Rhys Carre - who both make their Test debuts - fit that category, along with the likes of centre Scott Williams, plus fly-halves Jarrod Evans and Rhys Patchell.
Navidi added: "There are still positions up for grabs. There is plenty to play for, and opportunities for boys to show what they have got.
"The boys need to go out there and do the job. That's the best way to do it - think about tomorrow and let Sunday take care of itself."
On his captaincy role, Navidi said: "It is a massive honour. I've had loads of messages from people, which is nice, and my family are ecstatic as well.
"I will try and keep the emotions down. It's another game of rugby, but obviously nice to lead the team out, embrace the moment, and then get into it.
"I am not much of a talker, to be honest. Hopefully, I can lead from the front, and everyone else will follow.
"To be honest, I have never thought about it, with the leaders in the group with Wales.
"You have got Alun Wyn (Jones), Ken Owens and Jonathan Davies, who are massive figures in the team, and it's something that I've never thought I would come across - I thought just getting the red jersey is enough - so it will be nice."
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