Is calling someone a Mexican racist?

I was just informed by my family that I was racist by saying a soccer midfielder on our team played his position like a Mexican was a racist comment, and they mere use of word Mexican was racist. It was not an insult btw.

Number One, Mexicans are great soccer players. They have a style of play that is great by moving ball to a spot stopping or moving slowly to then passing to another spot but different than ours. We use a style of always moving and trying to hit moving players with the ball on the run player not keeping ball that long then passing to another. Both have advantages and disadvantages. (One obviously requires more energy.) I meant that he was playing with a style that was not working with the rest of the team. (Which is why on 14 goals scored he was only player on offense with zero goals and zero assist. We are counting on him to score goals this year and had the ball a ton but was not aggressive.

If not Mexicans, what are me supposed to call them, they are not Spanish and I have been chastised by actual Spaniards that they are very offended by referring to Mexicans as Spanish.