Jurgen Klopp's side were beaten 3-0 by the Italian giants at Murrayfield in Scotland on Sunday, much to the disappointment of the 70,000 supporters watching on from the stands.
The Reds have only picked up two wins from their six summer fixtures to date, with a trip to Geneva to face Lyon up next on Wednesday before next Sunday's Community Shield clash with Manchester City.
Liverpool have been without a number of key superstars during their pre-season campaign, including Alisson Becker, Roberto Firmino and Mohamed Salah.
All three men are expected to report for training on Monday following extended breaks after international tournaments, with Naby Keita and Xherdan Shaqiri also set to re-join the squad this week having recovered from injury.
Sadio Mane will return slightly later after reaching the Africa Cup of Nations final with Senegal on July 19 and Robertson is eager for the group to reunite in full before the start of the new season.
Speaking after the defeat to Napoli, the 25-year-old told Liverpool's official website: "The lads coming back, even if they don’t play, it gives you a lift when they train and with the way they go about their business.
“It doesn’t matter if they play on Wednesday or not, that’s completely up to the manager three days in, but that’s irrelevant: if they’re back in training and back around the place then it makes a difference.
“Mo and Bobby are two of our main men and Alisson was magnificent last season. They are huge characters in the changing room as well so that’ll be massive for us, and then Sadio will come back the following week.
“Once we get the whole team back together, and I think Shaq and Naby aren’t far off too, they’re players that are familiar around the set-up and around the system and that’s what we need. The quicker we get all of us back together then hopefully the better.
“But it’s not anyone else’s fault, the young lads or whatever who have come in, we’ve all not been good enough and maybe Bobby and Mo and people like that will give us the lift that we need. Hopefully, that does happen.”
Klopp has had the chance to blood some of the younger members of his squad in the absence of household names, with the likes of Rhian Brewster and Harry Wilson given the chance to prove themselves.
Liverpool's newest signing Harvey Elliott was granted his debut against Napoli and Robertson praised the 16-year-old before highlighting the overall impact the academy stars have had this summer.
“They’ve been great [throughout pre-season] and when young kids come in it’s a breath of fresh air sometimes,” the Scotland international added.
“Harvey Elliott only signed this morning and he’s come on and done magnificently for 15 minutes. He’s only 16 years old and I think people forget that.
“Rhian’s had a great pre-season, Harry Wilson looked good when he came on today. Look, we need these players to push us and they need to push us in every single position and if they do that then the gaffer will give them the chance.
“Fair play to them, when they came on and we were all off then it did look better. I was watching and it looked a lot better than we felt in the first half so credit to them.
“But now it’s up to us to put in the performances, we’ve got one more game before it gets competitive and we need to get up to speed now.”