Ex Ibrox favourite has been at the centre of some transfer-related controversy in South America

Ex-Celtic flop Efrain Juarez has sensationally quit his managerial post at Colombian double winners Atletico Nacional in protest over their transfer policy, including the club’s failure to sign Rangers striker Alfredo Morelos.

The Mexican coach stormed out of the Medellin outfit after reportedly becoming frustrated with a number of different factors relating to the club’s transfer activity, including their slow progress in attempting to turn Morelos’ loan move from Brazilian side Santos into a permanent deal.

Ibrox favourite Morelos helped Nacional to a league and cup double as he displayed flashes of his old form by scoring seven goals in 18 starts after a dismal spell with Santos.

However, talks over a permanent transfer stalled with the Brazilian’s, who appointed former Ibrox manager Pedro Caixinha as their new head coach last month.

Juarez successfully appealed a stunning three-year ban placed on him by Colombian authorities after he was heavily penalised for ‘excessive celebrating’ in a derby Cup win over Independiente Medellin.

And reports in Colombia have suggested he was left furious at the delay in trying to sign Morelos along with the shock arrival of Ecuadorian full-back Billy Arce without his knowledge and the decision to sell two players - Pablo Ceppelini and Alvaro Angulo.

Juarez previously admitted in an interview with The Scottish Sun that he enjoyed taunting Morelos over Celtic’s Old Firm record against Rangers. He joked: “I think it’s one or two derbies that Celtic and Rangers have played already and I was always like ‘we’re gonna kill you’ and he was like ‘no chance’. Sometimes it’s ‘you have been lucky’ or ‘oh the referee...’, he always complained because Celtic always win!

“When we (Celtic) are in the Champions League and they (Rangers) are in the Europa League, I always say the big club plays on a Tuesday or Wednesday. But in that situation (an Old Firm), we always talk about how big a game it is.

“I remember in my first season we played about seven or eight Old Firms and I had a chance to play in them. Alfredo also played in a lot of them, so we have a lot of chats about Scottish football. He talks about Rangers, I talk about Celtic.”