Paris Saint-Germain chased Monaco all last season before losing the French league title by eight points.

The tables have been turned this season, though, and Monaco is now lagging behind.

While PSG is very much in the ascendancy, Monaco’s season threatens to unravel after early elimination from the Champions League and a tough start to its title defense.

A win at Monaco’s Stade Louis II stadium on Sunday night will move league leader PSG nine points clear of second-place Monaco. And that would put PSG in prime position to reclaim the title it won four seasons in a row before Monaco ended that run.

Given the erratic nature of Monaco’s rebuilt lineup, and the power of PSG’s attack, a PSG win is hard to tip against. PSG crushed Celtic 7-1 in the Champions League on Wednesday night to take its goal tally for the season to 67 in 18 games.

Monaco is a vastly inferior team to the one which reached the semifinals of the Champions League last season.

Tuesday’s 4-1 home loss to Leipzig sent Monaco tumbling out of Europe at the group stage, and prompted a stern rebuke from club vice president Vadim Vasilyev.

“We failed in our European campaign. There are difficult moments in football and this really is one of them,” Vasilyev said. “I didn’t like the fact the players’ heads dropped so quickly.”

But he should look a lot closer to home before pointing the finger. For it would have doubtless been a far better campaign had the club not sold so many of its best players from last season. Monaco’s ability to spot talented young players and turn them into potential stars is a great money-making scheme, but it seems to have come at the price of genuine sporting ambition.

Initially, during a television interview with soccer show Telefoot late last season, Vasilyev had assured Monaco fans the club would not sell more than two of its highly sought-after players.

Monaco ended up selling five players.

Worse still, one of those players further strengthened PSG’s mighty attack when 18-year-old forward Kylian Mbappe joined PSG in a deal worth 180 million euros ($216 million).

Wide midfielder Bernardo Silva and left back Benjamin Mendy went to Manchester City and defensive midfielder Tiemoue Bakayoko joined Premier League champion Chelsea.

Monaco stripped the spine of a successful team.

The other significant departure was forward Valere Germain to Marseille. While he is not in the same category as the other four in terms of market worth and talent, Germain came through the ranks at Monaco to become a versatile and influential team member.

“Monaco wasn’t at the right level this season in the Champions League,” coach Leonardo Jardim said after the loss to Leipzig. “We need to build a stronger team for next season.”

Jardim pledged that Monaco will “arrive in this competition better prepared next season.”

That might prove to be wishful thinking, because qualifying outright in second place remains complicated.

Both Marseille and Lyon have improved considerably and could maintain a sustained push for second spot.

Heading into this weekend’s matches, Lyon was three points behind Monaco in third place and Marseille four points back in fourth.

PSG, meanwhile, is doing what Monaco did last season: tearing teams apart and scoring almost at will.

In the league, PSG has netted 43 goals in 13 games and at this rate is on course for 126— which would crush Monaco’s formidable tally of 107 from last season.

Edinson Cavani is now arguably the most lethal striker in Europe and took his tally to 21 in 18 games after netting twice against Celtic.

Neymar also scored twice against Celtic, but has not hit top form yet. If he does, PSG’s attack could become even more dangerous over the coming months.

Monaco, which is far too dependent on top scorer Radamel Falcao, must find answers fast before it drifts out of contention in Ligue 1.