If you take the last 40 days in isolation, it has been a wonderful time to be a Cardiff City fan.

Grimaces, grumbles and heads in hands have given way for smiles, tweets in full capital letters, Mick McCarthy GIFs and zoomed-in photos of his assistant Terry Connor.

Of course, that is unfortunately the modern, digital way of fans showing their glee. Because, if supporters were allowed back in the stadium and the world was back to normal, there would be screams, hugs and songs about Kieffer Moore.

With so much frustration, disappointment and heartache, both on and off the pitch, for Cardiff City fans this season, this wondrous six weeks have been bliss.

That is largely thanks to McCarthy and the manner in which he has galvanised this talented squad of Cardiff City players.

Here, we take a look at what's changed...

Galvanise confidence-sapped players

When he took over, he himself after his first training session admitted there were a number of diffident players and stars who looked down on their luck.

There was also a culture of laying blame on others when something didn't come off and the manager even stopped one training session to tell them to cut that out right then and there.

It was the manifestation of a disappointing and frustration start to a season which promised such hope, but saw City lying in 15th place in the table.

So, undoubtedly, the first thing he did was lift the morale. Football is all about confidence and he understood his first job was to make these players believe that they were good enough to box their way into the top six, rather than kick those beneath them in the relegation zone away.

A six-game losing streak, which brought Neil Harris' reign to an end, had driven City's confidence into the ground and it was no mean feat to pick up the pieces and meld them back together again.

But, after a rocky start against Barnsley which saw City 2-0 down at half-time, Cardiff have not looked back since.

Spot-on tactics and stripping back to basics

The next thing on the checklist was to implement the right tactics for this squad to produce at least the sum of their parts.

McCarthy, as he reiterated in his post-match comments on Tuesday night when asked about Wayne Rooney, is comfortable in his own skin. He has spoken before about how he is at piece with his crooked nose, white locks and receding hairline and that translates into his management.

Like it or lump it, this is Mick McCarthy. It might not be fashionable to cede 73 percent possession in modern-day football, like City did on Tuesday night, but did Derby County ever look like scoring? No.

Should Cardiff, who had the ball just 27 percent of the time, feel aggrieved they didn't score six or seven? Yes.

Their last home game against Preston? Just the 36 percent possession. The score? 4-0.

To hell with this so-called 'modern style', this is the Cardiff so many fans grew up with and adored so much. It's all killer, no filler.

McCarthy has made no bones about what he wants from this Cardiff side. He wants them to be solid and unyielding at the back; he has five very good defenders and two more than capable sitting midfielders and City are more than comfortable not having the ball for long periods.

The centre backs, or central midfielders, mop up the ball and look up before lumping it up to Kieffer Moore, or occasionally to Josh Murphy or Sheyi Ojo down the channel. Get out of your own half and play with it near their goal.

It always looked as though Neil Harris was just searching. Searching for the right fit, both for him and what he perceived the football club wanted.

Harris tried implementing a passing style at the start of the season and it didn't work. He reverted to a more direct route, but it still masqueraded as some sort of hybrid system, with the midfielders often getting overrun, the defence exposed and the wingers unsure and tentative in bombing forward because of having to fulfil their defensive duties.

McCarthy appears to have gotten rid of all the uncertainty. He has stripped it back to basics, in the most positive sense of the phrase, and given more clearly-defined roles.

The manager has got the best out of the very useful tools he has at his disposal.

He has three giant centre backs in his squad who are uncompromising in the air and work better, and look far more comfortable, with the extra cover if they are dragged out of position. So, he has played all of them together.

Perry Ng has looked an excellent signing and has been terrific at both ends of the pitch, while Joe Bennett, whose injury on Tuesday night might have sadly ended his season prematurely, has looked somewhere near his best the last 10 games.

Cardiff's defence was their biggest problem in the first half of the season, it is now one of their biggest strengths.

At the other end of the pitch, though, City are rampant. Incredibly, Cardiff are now the Championship's second-highest scorers with 53 goals, behind only Brentford on 61.

The long throw looks a massive threat again with Sean Morrison and Aden Flint now the big targets at the front post and Kieffer Moore lurking behind.

Harry Wilson's set-piece deliveries have been pinpoint, too, and Cardiff's huge players in the box are virtually unstoppable. Bournemouth boss Jonathan Woodgate said it was like "the land of the giants" after his Cherries got beaten up on the south coast last week.

Free-scoring City look a threat in open play, too

And while that is all well and good and Cardiff are utilising their strengths, they now have a swagger and a verve in open play, too.

At the start of the season, there was a huge reliance on set pieces, while their patterns of play in attack looked far less cogent. The wingers were cutting inside and not feeding Moore's strengths, Harry Wilson had too many backtracking duties and, as mentioned above, Joe Ralls was playing far too advanced.

Now, though, with these more clearly-defined roles, it has released the shackles on City's quality attacking players. The wing backs are providing the width and the likes of Kieffer Moore, Sheyi Ojo, Josh Murphy, Harry Wilson and Leandro Bacuna have sole licence to attack.

Cardiff have 23 goals in 10 games under McCarthy and, yes, while many have come from throw-ins, set-pieces and the like, there have also been some stunning strikes from open play.

Josh Murphy looks to the manor born in his new role as a second striker, scoring two and assisting two under McCarthy. Sheyi Ojo is the same; he has the same goals and assists as Murphy since McCarthy took over.

Josh Murphy is one of the players to thrive under the new manager

Harry Wilson has been an assist machine since he came on against Millwall in McCarthy's second game in charge and also scored a world-class goal in the win over Luton Town.

Harris' insistence on playing Junior Hoilett at the beginning of the season frustrated many. The Canada international endured a sub-par first half of the campaign and held back the potentially pacy, exciting and potent forward line.

Joe Ralls was sometimes used in an attacking midfield role far too often, too, and it stymied the danger going forward. Ralls has a big part to play in this side, but it isn't as No. 10, he would slot in perfectly at the base of the midfield, with his doggedness and industry, and that, you feel, is where McCarthy will play him.

McCarthy has fans happy and smiling again

Importantly, McCarthy has fans happy again. They cannot wait for the next game and are excited to watch their team play.

When Cardiff were at their worst this season, supporters appeared to be almost dreading games and had their scathing tweets loaded and ready for the full-time whistle. In truth, it wasn't a particularly nice atmosphere.

But that is the demand of the fan base, who believe this club is good enough to be plying their trade in the Premier League next season.

Now, though, some are dreaming of promotion once again. And why shouldn't they?

It had been a tough watch for much of this season. City were stuttering and stumbling and struggling to rag the gear stick out of second.

Now, with seven wins in 10 games under their belts, McCarthy's Bluebirds are really motoring, applying real pressure on those above them who have occupied the play-off spots all season.

But there are just a dozen games to go now and the play-off spots are well and truly up for grabs. City moved up into the top six again after the Derby rout, but chasing teams Bournemouth and Barnsley play on Wednesday night and could well go above them again.

But all Cardiff can do is keep winning. Another team keeps getting put in front of them every few days and McCarthy is swinging his bat and knocking them out of the park.

Will anyone want to play this Cardiff City side at the minute? Or, if we dare to dream, will they want to come up against them in the play-offs?

I don't think so, not for one second.