Rising Spanish star Carlos Alcaraz revealed that Rafael Nadal and Andrey Rublev were the two players who impressed him the most during training. Alcaraz, 18, had the opportunity to train with Nadal on several occasions, as the champion of 21 Grand Slams, a record, took him under his tutelage.Nadal, a former world No. 1, is helping Alcaraz by giving him advice, as he hopes the 18-year-old will unleash his full potential. Besides Nadal, Rublev was the player who also impressed Alcaraz during training. “The truth is that it is difficult for me to be surprised because I know almost all the player …