Pep Guardiola insisted on Monday he had no idea whether Europe's grandest clubs would be worried about Manchester City in the Champions League this season. If they were not before, surely they will be now.
It is hard to argue that this game was trickier than most people gave credit for, given the emphatic scoreline, but Basel have beaten Chelsea, Bayern Munich and Manchester United twice at St Jakob Park in recent years, and only lost narrowly to Real Madrid and Paris Saint-Germain.
In fact, they had won four of their five Champions League home games against English opposition. Throw in the fact that City had won just one of their six knock-out ties, and that even Guardiola has a poor away record in his knockout ties (just four wins from 22), it does highlight that this was not necessarily a walkover, and that it would take a special effort to win comfortably.
Of course, City are a special team. Even if you believe this game was barely a test of their quality at the top level, and that they should have won comfortably anyway, it surely serves as proof, if nothing else, that they are living up to lofty expectations.
Should they complete the job and qualify for the quarter-finals they will certainly face better sides further down the line, but even Europe's most established super powers will be eager to avoid Guardiola's side.
"I don't know, really I don't," the Catalan stressed at his pre-match press conference when asked if the likes of Real Madrid will fear the Blues. "I don't know if we are ready, I have a lot of confidence in the guys but this competion is special. Our target is to do better than last season, the quarter-finals would be better, and after that we'll see."
It looks very likely that we will soon see. The Premier League leaders did still have their shaky moments, particularly at the back, and particularly in the opening exchanges. Vincent Kompany was a surprise inclusion, given John Stones and Aymeric Laporte are both above him in Guardiola's pecking order, and he looked particularly vulnerable as Basel surged forward on the counter-attack several times in the first 15 minutes.
Yet it was Nicolas Otamendi who was most obviously caught out with the game still goalless; the Argentine bodychecked Dimitri Oberlin in the area but the referee decided against awarding a penalty.
From there, City barely looked back. They have enough ways of scoring goals so when Ilkay Gundogan heads in a corner you know you're in for a tough night. Sure enough, Bernardo Silva looped in a fine dipping effort and Sergio Aguero, full of confidence from his blockbuster fourth goal against Leicester City at the weekend, let fly from range and found the bottom corner.
There were a couple of shaky moments at the back for the rest of the first half but, like Basel's earlier forays, they were quickly forgotten when Gundogan found the net again. This time a sublime curling effort from outside the area.
That was the signal for Leroy Sane, returning from an ankle injury ahead of schedule, to get ready for action. With him fit, City have even more weapons. And David Silva didn't come on until past the hour mark, either.
Guardiola was still not completely happy, however; the way he slapped his hands on his thighs on numerous occasions throughout the match suggested his men were actually on the end of a heavy beating. The performance may not have been perfect but those standards will ensure there is no slacking from here on out.
If City can push on through March they can be crowned Premier League champions in early April. That would afford them the opportunity to rest their star men for big games in the FA Cup and, more importantly, the Champions League.
The thought of this group of players with fresh legs and focused minds heading into the latter stages of the season is a scary thought for any team they will face, no matter who they are.