Andre-Pierre Gignac is steaming down on goal. The Marseille hitman who, when his side travelled to Monaco earlier this season, had already reached double figures in his goalscoring tally, sees the Monaco goal gaping in his sights but he has just has one problem — defender Aymen Abdennour.

Abdennour is following almost harassing and cornering Gignac for the ball. The Tunisian-born defender standing at 6ft 2 proudly wears the No. 5 shirt of AS Monaco and is working overtime to keep a clean sheet and stopping what would be a fatal pass into the heart of the area. Once that ball is played Abdennour will know a one on one with the goalkeeper will most likely result in a goal. He ushers Gignac instead onto a one on one against him, the timing is key.

He is waiting for a loose touch, the touch that signifies that the player is ready to make up his mind and at that point Abdennour gets into a position to show Gignac away from goal and ultimately block the pass. Abdennour knows if he gets this right then there is no way that Gignac can play the ball around him or through him. Abdennour will use his pace and experience and another chance will have been diverted.

Abdennour has been the heart beat of Monaco, a club who arguably has produced the best defensive displays in Europe this season but it wasn’t always like that.

Monaco had started the season with fans protesting at the gates and threatening to boycott the games and return their season tickets. The reason had been the so called lack of ambition after the sale of James Rodriguez to Real Madrid. But then Radamel Falcao was loaned out to Manchester United for the season and it was easy to see the fans frustrations – because up front stood the lone figure of Dimitar Berbatov who had surely seen his best days years ago.

To make matters worse Monaco, last season’s runners up got off to a poor start in Ligue 1. Losing at home to Lorient 2-1 and then being thrashed away to Bordeaux 4-1.

The Champions League was different where in an admittedly fragile group the team started to chalk up wins and clean sheets. They finished the group stages conceding just one goal and winning the group. However, domestically the team was struggling in mid-table. There could be little doubt that their high profile departures in the summer had hurt the club.

With pressure on coach Leonardo Jardim to deliver, the club with no real quality up front instead concentrated on defense. This all came to ahead after another poor display had seen the team fall to Rennes 2-0. And then it all changed.

After the Rennes defeat, Monaco went 770 minutes without conceding a goal in the league. To date they have 14 clean sheets from 28 games and have conceded just two goals in the league since November 29th, 2014.

This attitude towards defense has reaped dividends and Monaco have reached fourth place, just three points behind Marseille and a Champions League place for next season.

Abdennour has seen a few changes in his teammates in the back line. But he has been the one constant player at center-back. At 25, he has just signed a one-year contract extension that ties him to the club until 2019. Though, it would be no surprise to see him play for the likes of Barcelona or Bayern Munich in a season or two.

This week Monaco has the chance to knock out Arsenal, after they pulled off a shock 3-1 win in London in the first leg of the Champions League. If they can complete their task, and with this defense, could we realistically say Monaco are dark horses for the competition themselves?