One of Chelsea’s stars of pre-season this summer has come from what many would describe as an unlikely source. Marc Guiu joined the club earlier in the transfer window from Barcelona, and was thrown in to the starting side immediately for their friendlies in the United States. He has started all but one game this summer, with the side looking better immediately after his introduction in the defeat at the weekend to Manchester City. READ MORE: Ranking the top five players on Chelsea’s pre-season tour so farEnzo Maresca has stated he has been impressed by Guiu already, with him certainly doing e…