Chelsea sent a scout to Celtic Park on Thursday evening to check up on Lazio midfielder Sergej Milinkovic-Savic in action against Celtic in the Europa League.
The midfielder completed all 90 minutes in the Europa League group stage fixture as a late Celtic goal saw the Scottish champions edge out Lazio 2-1.
Milinkovic-Savic has been linked with a host of Europe's biggest clubs over the last 12 months and the midfielder appears to be on Chelsea's radar.
The Blues had a scout at Celtic Park to watch him in action, according to Italian outlet Tutto Mercato.
Chelsea are still operating under a transfer ban, but their recruitment work has not stopped and the Blues want to be ready to make additions when they are again free to complete signings.
The 24-year-old has turned out in all Lazio's three Europa League game so far this season and scored and provided an assist in a 2-1 win over Rennes.
Milinkovic-Savic is now approaching the 200-appearance mark for Lazio, with 174 outings in a light blue shirt to his name so far.
The Rome giants have the Serbia international under contract until 2024 and he would be likely to be an expensive purchase for Chelsea.
