Eintracht Frankfurt have exercised their option to complete the permanent signing of influential wing-back Filip Kostic from Hamburg.
Serbia international Kostic's superb performances on the left side of Adi Hutter's top-four hopefuls have convinced the club to commit him to a four-year contract through to June 2023.
The 26-year-old initially joined on a two-season loan deal following Hamburg's relegation at the end of last term and has flourished in a team featuring Ante Rebic and in-demand striker Luka Jovic, who is reportedly set to join Real Madrid.
Kostic starred in Frankfurt's run to the Europa League semi-finals, scoring four times, and has added a further six goals and 10 assists in a Bundesliga campaign that could end with Champions League qualification.
"Filip has been a really lucky find for us," said Eintracht sporting director Fredi Bobic, who took Kostic from Groningen to Stuttgart in 2014.
"He is energetic, focused and adaptable, and that has helped him make a real contribution to the success we've had this season."
Frankfurt must secure more points than Borussia Monchengladbach and Bayer Leverkusen on the final day of the Bundesliga season if they are to climb from sixth to fourth.
That looks to be a tough ask as Hutter's side prepare to visit Bayern Munich, who require only a draw to effectively put the title beyond Borussia Dortmund's reach.