A first-half goal from Omar Marmoush took Eintracht Frankfurt to a 1-0 Bundesliga win at St Pauli on Saturday amid growing speculation that the Egyptian star is on the brink of a move to Manchester City.
Before the game, Frankfurt sporting director Markus Kroesche confirmed "a club had got in contact" about Marmoush, with Sky Germany saying the forward had already agreed personal terms with the struggling English champions.
Marmoush was on target in the 32nd minute against his former club, calmly turning inside the box before firing a shot into the top corner to give Frankfurt the lead.
The goal was Marmoush's 14th in 16 Bundesliga games this season, taking him level with Harry Kane at the top of the scoring charts. The 25-year-old also has eight league assists.
"We did plenty to keep a clean sheet today," said Frankfurt captain Kevin Trapp.
"There's definitely a few things we can improve on," the goalkeeper added.
Victory kept Frankfurt in third place, six points behind leaders Bayern who visit Borussia Moenchengladbach later Saturday.
Elsewhere, Freiburg leapfrogged Borussia Dortmund into sixth with a 3-2 home win over Holstein Kiel highlighted by a stunning free-kick from captain Christian Guenter.
Kiel's Nicolai Remberg unwittingly diverted an Eren Dinkci cross into his own net on 23 minutes, before Guenter sent an excellent dipping shot into the top corner from wide on the right-hand side.
Freiburg's Vincenzo Grifo added a third although Kiel's Phil Harres made the home side sweat with two goals in the final five minutes.
Union Berlin's miserable week went from bad to worse, going down 2-0 with 10 men at Heidenheim just days after a German Football Association (DFB) sports court punished them for unruly behaviour by their fans.
The DFB court decided Union's 1-1 home draw with Bochum in December should be considered a 2-0 win for the away side after a home fan threw a lighter at the head of the visiting goalkeeper.
Union president Dirk Zingler slammed the decision pre-match as an "unfair scandal", saying the court was trying to make a "political example" of the club who have appealed the decision.
Bayern Munich loanee Frans Kraetzig gave the hosts the lead on the counter after 17 minutes in his first Heidenheim game before Union's Tom Rothe was red carded for a last-man foul.
Adrian Beck sealed the result with seven minutes remaining, giving his side a first win since September.
Mainz climbed past RB Leipzig into fourth with a 2-0 home with over lowly Bochum, with Germany forward Jonathan Burkardt scoring in each half.
A 29th-minute Mohamed Amoura goal took Wolfsburg to a 1-0 win at Hoffenheim.