At the Polo Grounds‚ Boston pitcher Pat Flaherty clubs the first grand slam by a National League pitcher when he connects in the 2nd inning off Hooks Wiltse of the Giants. Boston wins‚ 7 – 5.

National League president Harry Pulliam dismisses the Opening Day protests of Pittsburgh manager Fred Clarke over Roger Bresnahan’s shin guards. As yet, Bresnahan is the only catcher using them.

Three-Finger Brown and Christy Mathewson hook up in a pitching duel, with the Chicago ace emerging the winner, 3 – 2. Matty’s batterymate Roger Bresnahan commits two errors to cause Mathewson to lose his first of the year. Mobbed at the Polo Grounds after the loss, umpires Hank O’Day and Bob Emslie require police protection. The crowd is egged on by manager John McGraw, who will be thrown out of games seven times this year.

Hooks Wiltse pitches the New York Giants to a 6 – 2 win over the St. Louis Cardinals. For New York, it is their 17th straight victory to run their season record to 24-3. Despite the run, the Giants stand in first place by just one game over the Chicago Cubs.

The Highlanders swap P Walter Clarkson and OF Frank Delahanty – both siblings of future Hall of Famers – to Cleveland for P Earl Moore. New York is hoping that Moore will return to the form he showed before a Highlander line drive injured his foot the previous season, limiting him to six games.

Christy Mathewson tosses his second straight shutout, stopping the visiting Pirates, 4 – 0, on four hits. Lefty Leifield takes the loss. First-place New York has now won 10 in a row and holds a slim lead over Chicago.

Frank Pfeffer of the Boston Doves pitches a 6 – 0 no-hitter against the Reds. He will be known as “Big Jeff” until his younger, and bigger, brother Ed “Jeff” Pfeffer becomes a star hurler for Brooklyn in 1913.