According to Daily Mail, Chelsea director Michael Emenalo was in Spain to watch Anthony Martial in action as Valencia beat Monaco on Wednesday.
Chelsea have already completed the signing of Pedro from Barcelona and are now keen to sign a striker and a centre back before the window closes.
Emenalo was present at the Mestalla on Wednesday to run the rule over 19 year old Anthony Martial. The Blues have already made a £39m bid for the Frenchman.
The Monaco forward has been linked with a move away all summer and was subject to bid from Tottenham earlier.
Chelsea are keen to strengthen their attack due to Diego Costa’s injury problems and the uncertainty surrounding Falcao’s form.
Martial is one of the most talented young forwards in world football and can operate in a number of positions across the front three.
Jose Mourinho knows the importance of improving his attack if they are to retain the title. Chelsea are humbled at Etihad last week and their lack of depth in the attack was evident.
With just over a week left in the window, Chelsea are keen to secure the services of Martial and John Stones.
The Everton defender is keen on a move to Stamford Bridge and the Blues have had three bids rejected for the England defender.
However, Mourinho is determined to get his man and could make a fourth and final offer for the Everton star.