By Jude Summerfield Chelsea manager Enzo Maresca claimed his side showed great improvement in some areas in their 4-1 defeat to Scottish champions Celtic on Saturday night. The Blues were 2-0 down at half-time after goals from Matt O’Reilly and Kyogo Furuhashi and abject defending saw them concede another two before Christopher Nkunku grabbed a late consolation from the penalty spot Chelsea had opened their tour of the United States with an eventful 2-2 draw with Wrexham but Maresca said he saw positive developments from that game despite the heavy loss at Notre Dame Stadium in Indiana. He sai…