Manchester City's Champions League defeat to Barcelona was decisive and disheartening. Watching those two matches, any City fan would be hard-pressed to think that the Sky Blues are one player away from competing at that level.
Unless City land an elite centre-back in the coming summer transfer window, that is.
If City can do that, their European prospects will surge.
City are deep at nearly every position on the pitch. They have four capable strikers, one of whom (Sergio Aguero) is truly special. They have an embarrassment of riches in the midfield.
Goalkeeper looked to be a position where City would seek reinforcements. That is, until their rumored target—Barcelona's Victor Valdes—sadly ripped up his knee. Joe Hart's claim to the cage seems safe for now.
City are in fine shape everywhere, except for perhaps the most important position on the pitch: centre-back.
The troubles for City at centre-back started early in the season and have never quite resolved themselves.
Matija Nastasic's injury troubles and consequent poor form have limited him to 11 Premier League starts. Joleon Lescott has made 10 appearances in the league and is out of contract at the end of the season. At times, holding midfielder Javi Garcia had to play out of position at centre-back which led to mixed results.
All of these circumstances led to the signing of Martin Demichelis, who has become manager Manuel Pellegrini's first choice to partner with captain Vincent Kompany in the center of the City back line.
Demichelis has committed a number of high-profile errors, including drawing the red card and conceding the penalty to Lionel Messi in the first leg of City's Champions League tie with Barcelona from which City really never recovered.
Looking at the situation dispassionately, though, it is ridiculous to blame Demichelis for City's plight at centre-back. Demichelis was not signed to start every important match. He was signed to spell Nastasic and Lescott now and again.
Only when those two came up so small did Demichelis become the default choice to run with Kompany so much.
Whether City win the Premier League this season or not, though, they will almost surely look to buy a better centre-back. Arguably, if City fix that one position, the entire side will rise with that surging tide.
We have come a long way without discussing Eliaquim Mangala specifically, so let's go ahead and do that now.
Mangala has been on Pellegrini's wish list for some time. City wanted to pry both Mangala and his Porto colleague Fernando out of Portugal in January, per Chris Wheeler of the Daily Mail:
Manchester City will make another attempt to sign Eliaquim Mangala in the summer despite abandoning a joint £35 million bid for the FC Porto centre-back and his team-mate Fernando.
Ed Malyon of the Mirror wrote recently that where Mangala is concerned, City might do better spending their money elsewhere. Mangala is, to Malyon, "a promising defender with lots of positives but nowhere near a £30 million centre-back, let alone £40 million."
Malyon's analysis, in my respectful opinion, temporarily takes leave of the fact that what Mangala will cost means almost nothing to City.
It is true that City balked at Porto's asking price in January. But that was before City watched Barcelona slay, draw and quarter their defense (Demichelis worst of all) in their first foray into Champions League knockout play.
Put it like this: In the moment that Demichelis was hacking Messi down, what might City have been willing to pay for a better central defender? Exactly.
And yet, even with the game-but-overmatched Demichelis playing too big a role, City still have their league destiny in their hands.
That is why Eliaquim Mangala—or any significant upgrade over Demichelis at centre-back—would be a perfect fit at Manchester City next season.
The summer transfer window is for addressing weaknesses.
City really only have one.