The Australian has not managed to get beyond last-16 of a Grand Slam since making the quarter-finals at the Australian Open in 2015.
On Saturday, Krygios was knocked out by Kei Nishikori in the third round at Wimbledon, after losing 6-1, 7-6, 6-4.
“Nick is part of the next generation and the whole conversation but he will have to step it up,” said Philippoussis.
“He has got all the talent in the world, everyone knows that, but just having talent alone won’t get you there.
“It’s very important to improve other things – to get strong mentally and physically. Those are the two areas he would agree that he needs to improve.
“He needs to get on that pathway where he will be stronger, better and hungrier.”
Philippoussis believes Kyrgios, 23, should see fellow young tennis star Alexander Zverev as a role model.
The German is ranked number three in the world and has eight titles to his name.
“Zverev has the whole package,” added Philippoussis, 41.
“With his mind and work ethic, he’s the one I have my money on.
“Does Nick have the ability and the game? Absolutely. But there are other things.”
Meanwhile, Philippoussis was full of praise for 36-year-old Roger Federer, who is chasing his ninth Wimbledon title.
“It’s incredible that he’s still playing,” said the Australian on the 15th anniversary of his loss to the 20-time major winner in the 2003 Wimbledon final.
“I have so much respect for the guy in that he’s as hungry as ever.
“He wants to keep improving and that’s the sign of a true champion. He is just an incredible inspiration
“When he’s in trouble, he usually has four options. That’s the difference. Some other players may have two options; others just one.”
After making five consecutive Wimbledon finals between 2006 and 2011 — and winning two of them — Rafael Nadal had a tough time getting back there.
He had lost prior to the quarter-finals on each of his last five visits to SW19, as knee woes hindered his chances on the grass, and power-hitters blew him off the court.
But on Monday, Nadal booked himself a spot in the Wimbledon quarter-finals for the first time since 2011, defeating Czech lefty Jiri Vesely 6-3, 6-3, 6-4 to set up a mouth-watering showdown against No. 5 seed Juan Martin del Potro.
“Of course is an important result for me, no? Yes, that’s all. Of course, is important for me to be in these quarter-finals. Is true has been a while since I have been in that position,” said Nadal.
“At the same time I have been in that position a couple of times in my career, no? We are not talking about already that I played a final or I won the tournament. We are talking about I am in quarterfinals. That, of course, is a positive result.
“But when I come here, I come here thinking that I can do a good result, no? If not, probably I will not be here. When I arrive here, my goal is to do the things the right way, to try to give me chances to compete well. Sometimes the things works better, sometimes worst. My feeling last year I was not in this round, but I was playing enough well to be where I am this year. So happy for that.”
Here are some numbers surrounding Nadal’s run to the quarters:
3 – Nadal is bidding to do the Roland Garros-Wimbledon double in the same year for the third time in his career. Bjorn Borg achieved that feat in three consecutive years (1978-1980).
4 – Nadal has now reached 4 consecutive Slam quarter-finals for the first time since he reached 11 straight Slam quarter-finals between US Open 2009 and Roland Garros 2012.
7 – years since Nadal was last in the final-eight at Wimbledon.
16 – Nadal is on a 16-match winning streak – a stretch that included title runs in Rome and Roland Garros, prior to coming to Wimbledon.
18 – Nadal is targeting an 18th Grand Slam title, to close in on all-time men’s leader Roger Federer, who has 20.
35 – Grand Slam quarter-finals Nadal has now reached.
40 – Nadal has won 40% of the return points against his opponents’ second serve so far this tournament – the highest percentage among all quarter-finalists.
78 – Nadal has a 78.3% (65-18) winning record on grass throughout his career.
84 – Nadal has won 84% of his net points (66/79) – the highest percentage among all quarter-finalists.
Tennis has been one of the leaders in sport when it comes to utilising technology in officiating, with Hawk-Eye being used to help with line-calling for more than a decade now.
But several controversial calls were made this week – particularly during the fourth round match between Dominika Cibulkova and Hsieh Su-Wei, and the third round clash between Novak Djokovic and Kyle Edmund – that have highlighted deficiencies in the current officiating system.
With VAR (video assistant referee) making its debut this World Cup, many have pointed out that further use of video replay is necessary in tennis.
During the Edmund-Djokovic match, an umpire awarded a point to the Brit even though he had touched the net, the ball had bounced twice, and his pick-up sailed out.
On Monday, umpire Zhang Juan made a mistake during the Cibulkova-Hsieh encounter. Late in the first set, with Hsieh serving at 4-5, a Cibulkova ball was called long but Hsieh hit the ball back anyway and it landed comfortable inside the court.
Cibulkova challenged the call and Hawk-Eye showed it was in. Zhang then decided to award the point to Cibulkova even though Hsieh had hit the ball and was not at fault in any way. The right call would have been to replay the point. Even the crowd were chanting “replay the point”.
Hsieh asked for the referee to come to Court 18 and play was delayed for nearly eight minutes as both players argued and eventually Zhang’s decision was reversed and the point was replayed.
If video replay was available, it would have taken seconds for Zhang to realise how wrong she was.
Of course Cibulkova knew what happened and could have suggested to Zhang they replay the point, but instead the Slovak complained about the officiating during her press conference, and said: “It was ridiculous what happened there. It never happened to me in my career that this would happen. Just a player is complaining. Sometimes I’m also complaining because I think it was a wrong call.
“But it never happened to me that the umpire changed the decision. It was really ridiculous for me. I think it was really bad decision from the supervisor and from the umpire.”
Quite the unexpected take from Cibulkova, who surely knows replaying the point was the right call.
She then continued: “The umpire told me she doesn’t remember what happened after the ball. Is it my fault you don’t remember if she hit the net or if she put it on my side?
“The right decision was, of course, to keep the decision. I mean, how many times it’s happening that a chair umpire is changing the decision?
I think there should be, like, maybe one rule for this because you never know what’s going to happen. It’s only about the chair umpire, what he thinks on his mind. Sometimes they can be wrong or right. Even if they are wrong or right, they are not going to change. I’m just talking it was not right to change the decision that she made.”
At a time when tennis is very much open to change and introducing new things – the shot clock will be used to count down from 25 seconds between points at the US Open – it’s time to consider some form of video replay to help umpires make the right decisions in such situations.