Hamburg director of sport Frank Arnesen has warned clubs off South Korean forward Heung-Min Son, who has made a big impact at the Imtech Arena this season.
Son bagged a brace in Hamburg's 2-1 Bundesliga win over Mainz on Saturday, taking his tally to 11 goals in 28 appearances this term and 19 in 68 games for the German club since he arrived from FC Seoul in 2008.
His current contract has just over a year left to run and Arnesen says he is keen to hand the 20-year-old a new deal as interest grows in the South Korea international.
"Son, with his 20 years, is one of the players we would really like to keep hold of," he told NDR television.
"We are willing to push ourselves to our pain barrier for him."
Arnesen confirmed that contract negotiations are already at an advanced stage for the forward, who is attracting interest from clubs around Europe, even though no official approaches have been made.
"He still has a year to go on his contract and we haven't had any offers from other clubs," said Arnsesen
"We are at a good stage with him and his contract extension so I am positive that we will extend with him for the long term.
"We have to ensure that we extend his contract as quickly as possible so that he can be settled."
Svetoslav Todorov, Mark Kelly, Darren Anderton, Linvoy Primus and Vince Hilaire have all agreed to appear in the match at Fratton Park, which kicks off at 7.45pm.
It is also anticipated that IBV manager Hermann Hreidarsson and goalkeeper David James, both former Pompey favourites themselves, will switch sides for the last 20 minutes of the game as fans welcome the new era at the club.
Trust spokesman Colin Farmery said: "We are delighted these former Pompey legends have chosen to support what we are trying to do. We are sure their appearance will be a draw for fans.
"Since the news broke last week that PST were going to take on the club we have seen a spike in ticket sales, but we would urge fans to buy their ticket online or from the ticket office before the match to avoid queues on the night."
Pompey boss Guy Whittingham has pledged to field a strong line-up for the game which is also part of the Icelandic Premier League club's pre-season preparations.