PARIS — Tensions are creeping in at Paris Saint-Germain with questions raised as to whether Neymar and Kylian Mbappe — the world’s two most expensive players — are so far justifying their price tags.

PSG is unbeaten and has scored 43 goals in 13 games overall, yet the mood seems surprisingly quizzical ahead of Friday’s home match against Nice.

Both players were heavily criticized following in 2-2 draw at Marseille last weekend, which allowed second-place Monaco — the defending champion — to close PSG’s lead to four points after 10 league games.

Mbappe didn’t make any impact up front and omitted to track back whenever Marseille broke on the counterattack.

Neymar did score his seventh league goal since joining from Barcelona, but his red card gave Marseille the chance to dominate late.

It was the Brazil forward’s fifth red card since breaking into the Santos team in 2009 and, not for the first time, resulted from a petulant reaction.

And it almost proved costly. For the second straight league game, PSG needed an injury-time goal — this time from top scorer Edinson Cavani.

Criticism of Neymar this week centered on his lack of composure, his reluctance to track back, and his self-indulgence.

Neymar’s tendency to hold possession sees him invariably trying to dribble his way through teams, and often leads him to randomly drop deep into midfield to get on the ball as much as possible.

When he does pass, his preference to seek out Mbappe often comes at the expense of Cavani — who scored 49 goals in all competitions last season. Cavani and Neymar disagreed last month over who should take a penalty in a league game, and their relationship does not appear to be a particularly harmonious one.

Cavani’s patience could well be tested — yet again.

The Uruguay striker previously played second fiddle for three years when Zlatan Ibrahimovic was PSG’s star player, and whether he is prepared to do so again could prove crucial to the club’s chances of going far in the Champions League. PSG has failed to get past the quarterfinals despite huge investment since Qatari backers QSI took charge six years ago.

But after even bigger spending during the offseason — with Neymar and Mbappe costing a combined 402 million euros ($475 million) — a semifinal is surely the minimum target.

The attack of Mbappe, Cavani and Neymar is known as the MCN — continuing the theme for abbreviations first launched when Real Madrid’s BBC (Bale-Benzema-Cristiano (Ronaldo)) attack was compared with Barcelona’s MSN (Messi-Suarez-Neymar).

Although prolific in attacking terms, PSG’s trio causes an imbalance elsewhere on the field simply soaks up so much possession.

Patient approach play is negated in favor of quick passes up to the front three. In turn this means that the midfield invariably stays too deep and makes for a large gap between the midfield and attack— which then impacts on the defense.

Given that Cavani is the only member of the MCN who does any significant tracking back to defend, PSG’s low midfield block of three finds itself completely stretched and covering too much ground when other teams attack on the break.

“I’ve rarely seen PSG get pushed around so much in recent years,” former PSG winger Jerome Rothen said after the Marseille game.

If modest Marseille exploited such a weakness, teams with far bigger firepower will surely punish PSG later on in the Champions League.


NICE MEMORIES

Nice was the last team to beat PSG in the league, winning 3-1 at home on April 30 in a result that swung last season’s title struggle Monaco’s way.

But coach Lucien Favre’s Nice is struggling badly for form this time around.

Last weekend’s 2-1 home loss to Strasbourg was Nice’s sixth in the league this season — compared with just four last season — and Nice has lost its past four games in all competitions.

Despite this, and the fact that PSG is unbeaten at home in league play since April, 2016, Favre is looking forward to Friday’s trip.

“We’re delighted to go and play PSG,” said Favre, who guided the team to a 2-2 draw at Parc des Princes last season. “We’ll have to defend as a team and we’ll need to be more compact.”

Nice is expected to welcome back Mario Balotelli, who missed the Strasbourg match with a minor calf injury.

Balotelli has made a good start with eight goals in 11 games altogether.