Kylian Mbappe tension overshadows PSG's crunch Champions League fixture
PSG have suffered numerous humiliating defeats at this stage of the Champions League in recent years but they are ideally placed to advance to the quarter-finals this time after winning 2-0 at home to the Basque side in last month's first leg.
Mbappe scored the opening goal in that game but the following day the superstar striker informed PSG of his intention to leave when his contract expires at the end of the campaign.
Luis Enrique might have been expected to make the most of being able to call on Mbappe until then, but instead he has made a point of reducing his top scorer's playing time.
Mbappe was left on the bench for PSG's next game at Nantes, although he came on to score a penalty in a 2-0 win.
A week later he started as captain at home against Rennes, but was substituted on 65 minutes. His replacement Goncalo Ramos went on to score the equaliser in a 1-1 draw.
Mbappe has made almost 300 appearances for PSG since arriving from Monaco in 2017, but he had only previously been taken off earlier in a game either due to injury or with PSG already winning.
Yet last Friday he was hooked at half-time in a 0-0 draw at Monaco, and once again there was no question of him being injured or even of Luis Enrique trying to save his superstar for the Champions League.
"Sooner or later we are going to have to play without him, so I am trying to find the best way of doing so," the coach said.
His comments came after he pointedly declared in a press conference last week that PSG would have "a much better team" next season, by which time Mbappe is expected to be playing for Real Madrid.
Punished?
Mbappe, who is PSG's all-time top scorer with 244 goals, appeared eager to make a point that there was nothing wrong with him in Monaco as he emerged from the dressing room after half-time.
Having changed into a tracksuit, he walked around the pitch waving to fans and then took a seat in the stand beside his mother, rather than on the bench next to his teammates.
PSG can afford to experiment in Ligue 1 given they lead the table by nine points from Brest with 10 games left.
However, Luis Enrique's decision to handle Mbappe in this way ahead of such an important European date has been questioned.
"I don't understand. I get the impression that ever since he told the club he was leaving he has been punished by the coach, or maybe the punishment has been imposed by the directors," said Alain Roche, a former PSG defender and sporting director now working as a pundit for broadcaster Canal Plus.
"I think it is inappropriate to create such a controversy four days before a game as important as the second leg against La Real."
Mbappe has scored 32 goals in 33 games for his club this season, including four in the Champions League.
No other PSG player has reached double figures and Mbappe will surely start in San Sebastian as the French champions look to finish the job.
They have a comfortable lead against opponents who lie seventh in LaLiga and have won only once in nine games.
Then again the Parisians are all too familiar with dramatic collapses in Champions League knockout ties.
Two of their most notorious defeats came on Spanish soil in last-16 ties after they had won at home in the first leg.
Two years ago they beat Madrid 1-0 in Paris and then went ahead in the return thanks to Mbappe, only to concede three times in the second half and go out.
In 2017 they hammered Barcelona 4-0 at home only to cave in and lose 6-1 at the Camp Nou.
Another exit this time, against weaker opposition and given Luis Enrique's handling of Mbappe, would be disastrous for coach and club.