Manchester United coaches Phil Neville and Paul Scholes attended Wednesday night's Champions League semi-final second leg against Atletico Madrid - fuelling speculation that the pair were on a scouting mission to run the rule over Spain international Koke.
The 22-year-old midfielder produced a fine performance at Stamford Bridge to help Atletico book their place in the Champions League final, courtesy of a convincing 3-1 victory over Jose Mourinho's side.
Manchester United have been strongly linked with Koke over the past 12 months, with reports back in January claiming the Red Devils were still keen to sign the tenacious midfielder, despite the fact he signed a new deal with Atletico at the end of 2013.
Koke has been one of La Liga's standout performers this season and is expected to be part of Vicente del Bosque's Spain squad for next month's World Cup finals in Brazil.
United are keen to complete deals for their main transfer targets before this summer's showpiece tournament gets underway, while Dutch coach Louis van Gaal is expected to be named as the club's next permanent manager within the next few days.
It's unclear whether the 62-year-old wants Koke to be part of his setup, or whether Neville or Scholes even were on a scouting mission last night, but Manchester United fans will be hoping the hearsay proves accurate.