Manchester United are hot on the heels of James Rodriguez who is regarded as the South American Cristian Ronaldo.
United watched the Porto star for a seventh time this season on Sunday, according to The Sun.
Sir Alex Ferguson has been on the trail of Rodriguez for months and despatched a scout to watch him in Porto's Portuguese League game against Maritimo at the Estadio do Dragao on Friday night, the Daily Mail (http://bit.ly/RCVCUq) reported in an exclusive.
The 21-year old Colombia winger underlined his rating by scoring two goals and laying on another in a 5-0 win.
But United have been stunned after his asking price was hiked to £36 million, up from the initial rate of £24 million after he renegotiated his Porto deal.
United have a ready-made bargaining tool in unsettled Portugal winger Nani, who joined United from Sporting Lisbon.
The addition of Rodriguez will add more variety to United lethal strike force which already boasts of the likes of Robin van Persie, Javier Hernandez and Wayne Rooney.