The former Liverpool youth player was back on German soil having played in the country on loan with Freiburg earlier in his career and was on devastating direct form.
Kent ran at will against the Borussia Dortmund defence and one particularly tricky twisting run teed up John Lundstram to send Rangers 3-0 ahead shortly after half-time.
First half goals from James Tavernier and Alfredo Morelos had put Rangers ahead at the break and though Dortmund replied twice, they carry a 4-2 advantage back to Ibrox for the second leg next Thursday.
Match stats show Kent made four successful dribbles throughout the game and laid on three key passes in the momentuous win over the German giants and Hargreaves, an ex-Bayern Munich player watching for BT Sports saw hallmarks of one of the Bundesliga’s best in Kent’s display.
“It almost looked like it was Franck Ribery terrorising Borussia Dortmund the way he used to do for Bayern Munich,” said the former England international.
“I wouldn’t be surprised if teams in the Premier League or Bundesliga are looking because that is a performance that you have to sit back and think ‘wow, that is a special player’.
"He shocked everyone and the Dortmund players wouldn’t have known much about him but you can guarantee at the end of the game every player in the dressing room would have said ‘who’s that guy?’
“It was exceptional play to set up John Lundstram for Rangers’ third goal – the control and the quality. Running at players is Ryan Kent’s greatest attribute. I love watching Ryan Kent. Technically he’s absolutely brilliant.”
Kent moved to Rangers on loan in 2018 before making his deal permanent a year later. The year prior to his loan to Scotland, Kent spent a six-month spell on loan in Germany at Freiburg, playing six times with just one start in the Bundesliga before returning to Britain with Bristol City.
The winger’s contract at Rangers expires next summer and Giovanni van Bronckhorst has already admitted this week that talks over an extension will begin soon.