Liverpool have agreed a first professional contract with 17-year-old winger Mateusz Musialowski, a player who has already been called "Polish Messi" by Reds fans after a sensational solo goal in the Premier League last 18 last season.The effort from Musialowski, who joined Liverpool from Polish club SMS Lodz last summer when he was just 16, was named the Premier League's goal of the season in 18 years.At the time, the teenager even said that he had specifically modeled that side of his game at Messi by looking at the way the…