The last time Eintracht Frankfurt made the semifinals of the Europa League was in 2019, when they lost on penalties to Chelsea. The team has changed a great deal since then, but one attacking constant remains, Filip Kostic.

In the current Bundesliga season, the football statistics website FBref records the 29-year old averaging 6.96 crosses per 90 minutes, which puts him in the top 1% of full/wingbacks. If he's not supplying teammates with crosses, he attacks the opponent's last line of defence with his dribbling/ball-carrying abilities. He ranks in the top 3% for that too.

FBref also has him down as the best Bundesliga player in his position when it comes to supplying shot-creating actions (the offensive action that directly leads to a shot e.g. key passes, winning set-pieces, offensive duels). He has also managed to add an extra layer to his game by participating in link-up play while drifting into the half spaces.

Best yet in Barcelona

If he's positioned on the weak side (the opposite side of the pitch from where the ball is being played), he often cuts inside, attacking the space behind the opposing full back. This can then be followed by a chance on his very strong left foot, as was the case with his second goal against Barcelona at the Nou Camp.

While Kostic said his performance in the quarterfinal win over Barcelona was the best of his career, it hasn't always been easy for him to make an impact.

Kostic had unsuccessful spells at both Stuttgart and Hamburg and was relegated with both clubs. Sporting director Fredi Bobic brought Kostic to Stuttgart from Groningen in 2014, and four years later, Bobic moved to sign the Serbian again, brining the winger to Eintracht Frankfurt on a two-year loan with an option to buy after a year.

Before joining the club in Hessen, Kostic was used as a typical winger, providing width and speed in the final third but he was also seen as an "Ego Shooter,” a footballer who only plays for himself, only thinks about attacking and doesn't care so much for tracking back in defence. Additionally, he wasn't the most effective winger.

When joining Frankfurt, former coach Adi Hütter used Kostic's offensive skill set and trusted him to work defensively because of the winger's high work rate in training. With Hütter's preferred 3-5-2/5-3-2 formation, Kostic was allowed to cover the whole left wing which gave him enough space to utilize his speed and demonstrate his quality on the ball.

The right fit

This gave him the opportunity to shine in a new role as wingback, a hybrid between fullback and winger which is typically very vertical and occupys a specific side of the pitch. This means the player usually has to defend within the back five and attack as a winger up front.

Under Frankfurt's current head coach, Oliver Glasner, his role hasn't changed. In possession, Kostic's main task is to provide width and occupy a high position on the left wing in order to pin back the defending fullbacks. From there he can receive passes and create one-on-one situations followed by a cross with his strong left foot.

Out of possession, Kostic takes part in Glasner's press from his position in a back five as soon as the team's pressing is triggered. This means when an opponent passes the ball onto the wings, Frankfurt try to isolate them with Kostic pushing forward and putting pressure on the receiving player. If the press fails, or Frankfurt decide to go deeper towards their own goal, Kostic can track back and defend within their own formation. His high work rate helps Frankfurt close down passing lanes and defend more zonally.

The 29-year-old offers a well-rounded skill set, a powerful dominant foot, and a strong work ethic, which has moulded him into the perfect wingback for both offence and defence in the Bundesliga and Europe. With his contract running out in June 2023 and rumors of a move to Italy growing, Kostic's time in Germany might be coming to an end. But his eight years in the country have been an era of development.