Brazilian starlet Bruno Guimaraes is being tracked by Chelsea.

The Blues watched Guimaraes help Atletico Paranaense thrash Boca Juniors.

The midfielder started as his side ran out 3-0 winners in a Copa Libertadores clash.

Globo Esporte reports a Chelsea scout was in Atletico president Mario Celso Petraglia's box along with the son of a businessman who works with the 21-year-old ace's agent.

Shakhtar, Inter Milan, Lille and Napoli have all been keeping tabs on the defensive midfielder.