It marked the 13th time a Padres player has hit two or more doubles in consecutive games and the fourth time a Padre has done so in successive home games.
The last player to do so was Hall of Famer Tony Gwynn in 1998. Not only that, Alonso, who is in his first season with the Padres, became the first player to accomplish the feat at Petco Park, which opened in 2004.
Is Alonso's line-to-line approach to hitting the perfect fit for Petco Park?
"I don't think about the field. But I think it's a field where I can hit a lot of doubles," he said. "But if you look at it, at a smaller ballpark, I might be able to hit more home runs. But if it's going to be a doubles-type field ... then bring it on."
Alonso, who leads the team with seven doubles, hit 24 doubles in 358 at-bats in Triple-A last season in the Reds' farm system. He hit five more in 98 at-bats with the Reds. The previous season, Alonso hit a combined 38 doubles in 536 at-bats.
Alonso had 17 home runs last season, two more than he did in 2010. He doesn't have a home run yet in 2012, though he's come close a few times.
"I hit more home runs, which was a good sign that I was getting stronger," Alonso said. "I think it's going to be a process where I get stronger and maybe some of those doubles turn into home runs. But now ... doubles are the thing for me."