When Luis Castro started as coach of Benfica’s under-23s, he had plenty of talent at his disposal.While striker Joao Neves has been linked with a big money move to Manchester Unitedand Morato are the first team stars at the Estadio Da Luz. Another protégé, Goncalo Ramos, broke through at PSG alongside Cher Ndour, who both left Portugal for France. But of all the youngsters Castro worked with at Benfica, there was one he knew would make it to the top. That is why he felt deep satisfaction when he watched Paulo Bernardo work for Celtic in the Champions League.The 21-year-old has been a revelation at Parkhead since joining on loan from Benfica last summer. After settling in early, he is now a key player for Brendan Rodgers. As well as impressing in Europe, Bernardo scored his first Old Firm goal against Rangers in the Hoops’ 2-1 win last month. But Castro is not surprised by his progress.And with Rodgers at the helm, he became convinced that the sky was the limit for Bernard. Celtic have an option to buy him in six months, but the fee requested by Benfica is unclear. Castro, who spent four years at the club, believes that if Bernardo is available for £5m – it’s the ENDBecause he is convinced that like Jota before him, who was sold to Saudi Arabia for £25m, his Celtic can huge profits in the future. Castro told MailSport: “If they have the chance to sign Paulo, they will. The same with Jota and they sold him for a lot of money. If there is a chance, they will keep him in Glasgow.”For £4m or £5m, it’s Celtic’s highest offer. If that’s the price, it’s very cheap for Paulo. For a young player of his quality – who is getting better and better – that would be a lot for Celtic. I’ve trained many good players and Paulo is definitely one of them, I worked with Silva and Morato with Neves, who is now in the first team of Benfica..