Gary Neville has revealed he knew Wayne Rooney and Ruud van Nistelrooy were 'certainties' to be successful at Manchester United as soon as they completed their moves to Old Trafford.
Neville chalked up nearly 600 appearances for the Red Devils in a glittering career that saw him win eight Premier League titles and the Champions League twice.
He saw plenty of players come in and out of Old Trafford during his 20-year association with the club but has recalled knowing that both Rooney and Van Nistelrooy would be instant hits.
Dutch striker Van Nistelrooy joined United in 2001 for a British record transfer fee at the time of £19million from PSV Eindhoven while Rooney signed from Everton for £27m in 2004.
Neville revealed it took just one training session for Van Nistelrooy to convince him of his ability, while he already knew Rooney would be a success before he joined.
The Sky Sports pundit said: 'There were two certainties.
'The one who I already knew was Wayne Rooney. It wasn't even a risk, you just knew he would be absolutely unbelievable.
'Even though we had to wait for him to make his debut because he was injured, I never thought it would be a risk.
'The other one I didn't know but we spent a lot of money on him and it was Ruud van Nistelrooy.
'The first time I watched him in training, he did a shooting session and hit one and I went, "woah, you can't kick a ball like that". Sometimes you see things in training and just think to yourself, "that's a proper player".
'That was Ruud. He was the one who I didn't know beforehand that I looked at straightaway in training and thought he was unbelievable.
'The other one was Wayne Rooney and it was mesmerising to think what he would do for us.'
Van Nistelrooy scored a sublime 150 goals in 219 appearances for United over his five-year stay at Old Trafford.
During that time he won all four domestic cup competitions before leaving for Real Madrid in 2006.
Rooney, meanwhile, finished his United career in 2017 as the club's record goal scorer thanks to his record of 253 goals in 559 appearances.
Neville has previously called the Derby manager the 'best centre forward I ever saw at United'.
He said: 'For me he was the best centre-forward I ever saw at Manchester United and ever played with.
'I have him number one, up front, Cristiano Ronaldo alongside him in every single of the best United teams that I played alongside.
'That's the highest compliment I can pay him, because I played with Cantona, Hughes, Yorke, Cole, Sheringham, Solskjaer, Berbatov, Tevez, great strikers from all over the world, not just in England. But Rooney would be my number one.'