Mets legend Mike Piazza once criticized Pedro Martinez for lacking 'class' and suggested he should learn proper baseball etiquette 

Back in 1998, legendary baseball players Mike Piazza and Pedro Martinez were involved in a heated argument while playing for the New York Mets and Boston Red Sox, respectively. Martinez hit Piazza in his left shoulder with a ball. This kept Piazza out of action for some time. Because of this, Piazza had some harsh words for the starting pitcher.

Both Mike Piazza and Pedro Martinez started their professional careers with the Los Angeles Dodgers. From there, they would go on to create history independent of each other. Piazza would become a 12-time All-Star as he went on to hit 427 home runs. On the other side of the spectrum, three-time Cy Young Award winner Martinez would also become an eight-time All-Star. Both have been inducted into the Baseball Hall of Fame.

On June 5, 1998, in a game between the New York Mets and Boston Red Sox, Martinez pitched a ball that took the inside line and hit Piazza. This kept him out of action for the majority of the three-game series between the inter-league opponents. In subsequent interviews, Piazza said:

"It shows you that all that money can't buy you class. Maybe he should invest in some lessons on etiquette."

The Mets catcher used this statement to take a dig at Martinez's background. Pedro's brother Ramon went on to make it big in the Majors and also had a short feud with Piazza during his time at the Mets. Moreover, the Mets, as an organization, had bad blood with Ramon.

Martinez responded, "He wants to talk about class. Well, he was a millionaire since he was a kid. He's not a better person than me."

Mike Piazza and Pedro Martinez's time as teammates in 2005

After a successful spell with the Red Sox, where he won the World Series in 2004, Pedro Martinez signed a four-year, $53 million contract with the Mets. He was reunited with Mike Piazza, who was already in his seventh year with the Metropolitans. Back in 2005, Piazza said:

"What we've had in the past is in the past. ... We're teammates now. And I know that I'm going to go out there and do the best possible job I can do for him, and I hope he feels the same for me. So, that's it. I mean, I'm going to be his No. 1 supporter."

Mike Piazza, therefore, put their rivalry behind him and moved on. Martinez's debut season in New York would be Piazza's last. The pitcher posted a 15–8 record with a 2.82 ERA, 208 strikeouts, and a league-leading 0.95 WHIP. It was his sixth league WHIP title. On the other hand, Piazza received a standing ovation in his last game at the Mets Stadium.