Alonso had a suite filled with 30 people, with at least 30 more in attendance in the stands. Grandal said he had at least 170 friends and family members at Marlins Park. The duo expects even more Saturday.
Five of the Padres' runs came in the sixth inning, as the team turned a two-run deficit into a three-run lead en route to its 20th come-from-behind win of the season.
The Padres took advantage of an error and a pair of Carlos Zambrano walks in the sixth, sending a season-high-tying 11 men to the plate. Logan Forsythe led off the inning with a double and Jesus Guzman reached on an error. Zambrano walked Chase Headley to load the bases and then lost Carlos Quentin to walk in the Padres' first run.
It was the fourth time this season Zambrano walked in a run.
"Maybe he's scared to throw the ball over and they'll hit a grand slam," Marlins manager Ozzie Guillen said. "We're trying to figure it out, whether it is mechanic. We talked to him early, and he said he was feeling fine. The first couple of innings, we were very excited to have him on the mound. Everything went south pretty quick."
Grandal, playing in Miami for the first time in his big league career, then smacked the first triple of his career over the head of center fielder Justin Ruggiano to give the Padres the lead and chase Zambrano from the game. Zambrano had held the Padres to just one hit through the first five innings.
"That was a bullet," Black said. "The center fielder froze a moment. By that time it was too late -- the ball was over his head. That was a missile."
Alonso followed up the triple with a single to left field to plate Grandal and snap an 0-for-21 streak at the plate.
"Just have to learn from it," Alonso said of the slump. "This whole year has felt like a learning process. ... It's been more mental than anything. It's good and bad. You just got to keep going, keep grinding."
The Padres had six men reach base before recording an out in the sixth. The five runs were the second most San Diego has scored in an inning this season, as the team scored six in a frame three times.
The big inning came immediately after Friars starter Kip Wells escaped a jam in the bottom of the fifth.
The Marlins had men on first and third with no outs, but Wells got Emilio Bonifacio to ground into a fielder's choice that got the lead runner out in a rundown between third and home. Donovan Solano then grounded out to Headley for the second out, putting men on second and third. Wells intentionally walked Jose Reyes before Carlos Lee grounded into an inning-ending fielder's choice.
"To hold them at bay, to keep it right there, I really think the momentum swung back to us there," Black said. "You could tell that the Marlins were a little bit dejected after that. ... That gave us a little life."
Wells earned the win after pitching six innings and giving up two runs on five hits. He walked two and struck out four as he improved to 6-3 in 10 career starts against the Marlins.
The only blemish on his night came in the fourth when the Marlins led off the inning with three consecutive hits. Solano singled and Reyes followed with an RBI triple to extend his hit streak to 14 games. Lee then beat out an infield single to plate Reyes and put the Marlins up, 2-0.
After the Padres' five-run sixth inning, they were able to stretch the lead in the seventh. Alonso knocked in his second run of the night with a single, and former Marlin Cameron Maybin doubled to score Grandal, who had reached on a one-out single.
Grandal and Alonso combined to go 4-for-9 with five RBIs and two runs scored in their return to Miami.
"Just getting the first hit out of the way in front of your family, that's good," Grandal said. "I wasn't putting too much pressure on myself, but I was seeing the ball really well tonight."
Added Alonso: "It's everything I was hoping for. I was just happy to get the win."