Pittsburgh’s PNC Park makes its major league debut as hometown product Sean Casey leads the visiting Reds past the Pirates, 8 – 2. The Reds first baseman, who hit the first home run ever at Miller Park three days ago, goes 4 for 4 and again has the honor of hitting the first home run in a major league park’s history. The bat which was used to hit both historic homers is sent to the Hall of Fame.

On April 9, 2001 — Pittsburgh’s PNC Park makes its major league debut as hometown product Sean Casey leads the visiting Reds past the Pirates, 8 – 2. The Reds first baseman, who hit the first home run ever at Miller Park three days ago, goes 4 for 4 and again has the honor of hitting the first home run in a major league park’s history. The bat which was used to hit both historic homers is sent to the Hall of Fame.

Source
Baseball Reference April 9