Ex-Paris Saint-Germain star Valdo believes that when Neymar and Kylian Mbappe are on song the forward pair are a match for any defence on the planet.
Neymar was in fine form in Wednesday's Champions League comeback victory over Atalanta, redeeming himself in the final stages after missing two clear chances early on.
The Brazil international set up Marquinhos to bring PSG back level in the 90th minute and moments later set substitute Mbappe loose down the left to square for Eric Choupo-Moting, who sealed a 2-1 victory deep into injury time.
PSG missed Mbappe prior to his introduction, with the France sensation recovering from an ankle sprain and starting on the bench.
Valdo, who was part of the last PSG side to make the Champions League semi-finals back in 1995, believes that when fit both his Brazilian compatriot and Mbappe give the Parisians a crucial edge when going forward.
"When you're Neymar Jr. or Kylian Mbappe, it's easier not to doubt," the ex-midfielder, who also represented the likes of Benfica, Gremio and Cruzeiro during his career as well as picking up 45 caps for Brazil, told PSG's official website.
"It's true that Neymar missed two opportunities that he usually scores. But we could feel he was in the game. When he plays at that level, there's no tactical system to stop him.
"A bit like Mbappe or Messi. When it’s the right night, he's unstoppable. Neymar had a lot of space, and on counter-attacks he was really impressive.
"As for Mbappe... If I'm the Atalanta coach and I see Kylian Mbappe coming on, I'm already very worried. It already means it's impossible to stop him, you need at least two players to stop him and the same goes for Neymar, it's very complicated.
"That's the strength of having a squad like Paris Saint-Germain. Let's hope now that Kylian will be at 100% for the next game, so that the opponents can't sleep well."
PSG now face RB Leipzig in Tuesday's semi-final, after the German side overcame Atletico Madrid in a tense quarter-final tie on Thursday.
The second last-four clash will be disputed between Bayern Munich, who destroyed Barcelona 8-2 on Friday, and the winner of Manchester City's tie against Lyon.
