If Maradona would have had the chance to score 4 past any opposition in champions league, he would have had (from Metallist to Real Madrid), don't delude yourself on the words of a retired player that tries to make his legend status be bigger by subtly putting down current players' achievements.
Besides that point, you have to take into account that Maradona was played as a pure 10 in Napoli for example, in a more tactically righd scheme, where no.10 did no.10 stuff mostly by serving no.9 (Careca, a very good forward). So probably Maradona of today (assuming talent + added physicality of the game do not affect him but benefit him), would have probably also found himself in conditions to score a poker in knock out rounds of the CL (which in anyway you wanna see it, even if you're using to discredit a player, its a fantastic feat in a big match, the result was ridiculous cause he made it happen).
The big game theory is the biggest BS ever created in sports. No one can really define a big game outside finals and biggest rivalry game. If the player plays wonderfully in a semifinal but sucks in the final, he's a big game choker, or someoen that only shows up in non relevant games.
The final decisive game is just as important as all the other games that got you to where you are. You wouldn't be playing a decisive game if you wouldn't have performed in the past games. If Messi doesn't score those 4 goals vs Arsenal, and say no one in Barca is capable of scoring goals, and Arsenal takes a fluke goal, you'd be using that Arsenal match as a proof that Messi did not show up at a dumb QF CL game, where Barca gets eliminated, during their most dominant era. But because Messi scored 4, you decided it wasn't a big game.