Coach Martin Demichelis will be looking to strike a blow against his former employers when his RB Leipzig side host Manchester City in the Champions League on Wednesday.
Former Argentina centre-back Demichelis spent three seasons at Manchester City, winning the 2013-14 Premier League title and two League Cups.
Demichelis, who also won four league titles as a player at Bayern Munich, is now hoping to bring success to Saxony in a budding coaching career.
Leipzig have beaten City just once in six attempts, but may feel Enzo Maresca's men are vulnerable.
In their past three games, City have lost twice and won the other match on penalties, as the spectre of sanctions for breaching financial rules looms.
Demichelis, 45, was controversially handpicked by then-Red Bull boss Jurgen Klopp to take over in the summer.
To bring in Demichelis, Leipzig sacked popular coach Ole Werner, who had taken a young team back into the Champions League, while overseeing the development of Yan Diomande.
Real Madrid paid a reported 125 million euros ($140 million) for Diomande, just a year after Leipzig signed him for 20 million euros.
Demichelis was relegated from LaLiga during a short stint with Mallorca last season but Klopp and Leipzig had seen enough to convince them of his ability, after he oversaw a significant up-turn in the club's form.
After a rocky start with Leipzig, including a 4-1 loss at Como in the Champions League and a 6-1 thrashing by Bayern Munich, Leipzig have won three games in a row.
The Red Bulls sit just three points off top spot in the Bundesliga, but are in desperate need of points in Europe.
The 2020 semifinalists are 29th in the 36-team table after winning just one of three Champions League games this campaign.
'COMPETITIVE AURA'
Demichelis benefited from the tutelage of several big-name coaches, including Louis van Gaal, Manuel Pellegrini, Diego Simeone and his idol Diego Maradona.
Leipzig centre-back Maxime Esteve said Demichelis has brought a "competitive aura" to the club.
"Even in small games in training, you can see that the coach does not want to lose," Esteve told AFP and other media on Monday.
"When he misses something, you can see he's a little bit angry. You can see he stopped playing football not that long ago.
"You can see the aura of his competitiveness."
Esteve played under another former City player, Vincent Kompany, during his time at Burnley and said Demichelis reminds him of the Belgian, who is now coach of Bayern.
"It's funny because they both spend a lot of time in the gym. They want to stay fit, because they have a big history in football.
"They play in games in training and you can see they are quite competitive. They don't want to lose.
"They are really energetic and spend a lot of time at the training ground.
"They are perfectionists and want to sort out the small details as soon as they can."
Esteve also has experience defending against Manchester City talisman Erling Haaland in the Premier League.
The Frenchman acknowledged his side had played against freshly minted Ballon d'Or winner Harry Kane only two weeks ago, but called the big Norwegian "the best striker in the world".
"He's so powerful, so good with his head, so quick. He has all of the qualities to be a beast.
"So it will be a difficult game, but when you want to progress in football, you have to play against the best opponents. And you want to perform in this type of game."