Klopp handed Pulisic his debut at Dortmund and Liverpool had two bids for the 19-year-old turned down in 2016 after the German’s move to Anfield.
Liverpool have kept tabs on Pulisic ever since and are expected to make another move for him this summer following Philippe Coutinho’s £142million move to Barcelona.
However, United will not let the American teenager go without a fight and will accelerate a move for Pulisic if Liverpool solidify their interest, according to the Independent.
United believe Pulisic could fill the wide role that Mourinho was keen on signing Ivan Perisic to play and the teenager’s appeal to the American market is a huge plus point for the club’s hierarchy.
Though the United States missed out on qualification for the 2018 World Cup, much hope is pinned on Pulisic and he looks set to be the biggest name to emerge from American soccer since Landon Donovan.
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While Liverpool have cash to spend from Coutinho’s move to Barcelona, United believe they could hold an advantage over the Reds because of Dortmund’s interest in Henrikh Mkhitaryan.
The Armenian is open to leaving Old Trafford after a poor second season with the club and Dortmund have offered him the chance to return to the Bundesliga club.