"I have seen him from very close quarters and he is like a younger brother. Sandesh is the best centre-back in India right now," Gouramangi told ahead of India's World Cup qualifier against Bangladesh to be played on October 15.
"He should keep challenging himself and take his game to the next level. He has the potential to do that. He is 26 and this is the right time to realise his potential.
"I told you he is the best, but he can get better. That's how good he is," said the 33-year-old Manipuri who represented India in 69 matches between 2006 and 2013 and was rated as one of the best defenders the country has ever produced.
Asked what are the areas he feels Sandesh needs to work on, Gouramangi said: "I can't be specific. He is right there. You have seen him play and we all know how good he is. He just needs to keep pushing himself, stay fit and take care of the body. Time flies and he won't realise it. I always advise him to stay away from injuries as much as possible and keep working hard."
Sandesh is India's defensive mainstay and was a rock at the back in both their Group E World Cup qualifying games so far.
Exactly a month ago, India pulled off a famous 0-0 draw against Asian champions Qatar after narrowly losing to Oman 1-2 in their qualifying opener in Guwahati.
"India defended brilliantly in that game (Qatar) but I feel they were better against Oman. Yes, they conceded a goal late on but they should have won it on another day," said Gouramangi who was a vital member of the national side that took part in the 2011 Asian Cup in Doha, Qatar.
India missed talisman and leading goalscorer Sunil Chhetri in their match against Qatar as the skipper was down with flu. A longtime former teammate, Gouramangi said Chhetri, at 35, is still an inspiration for all aspiring footballers because of the way he carries himself on and off the pitch.
"He is a vegan now. It just goes to show that even after achieving so much, he has the hunger to do more. To not compromise on his body one bit and stay healthy. He is a living legend. I went to his place on his birthday recently and all I told him was to keep going. India will always need Sunil Chhetri," said Gouramangi.
"He is an inspiration for all the young players in the Indian team for the way he is on and off the pitch. These young guys in the team are lucky to have him."
On India's tie against Bangladesh, Gouramangi said that Igor Stimac and his boys should now look to continue the momentum and log a win against the lower-ranked side.
"You cannot be complacent against them. You never know they might spring a surprise. We must continue the good work and win. We are yet to do that in the qualifiers."
He heaped praise on India's Croatian coach Igor Stimac.
"I hear he talks to the boys a lot and takes care of them. These little things are so important. The team has been doing well under him and I hope he continues the good work," added Gouramangi who is now part of Bangalore United Football Club's technical team and is an AFC 'B' licensed coach.
( With inputs from IANS )