Playing his second game of season after recovering from a knee injury, Souza drove in a career-high nine runs and fell a double short of the cycle in the Suns' 24-2 rout of the Rome Braves.
"Let me tell you this, it was fun to watch," said Souza, who joined the team Friday after rehabbing tendinitis in his left knee. "It was amazing to watch. One guy set the tone and everyone else followed.
"I'm just trying to fit in here. I'm happy to have this opportunity."
The nine RBIs were one short of the South Atlantic League record. Asheville's James Barbe plated 10 runs on April 22, 1978, a mark duplicated last June 3 by Asheville's Corey Dickerson.
Selected by the Nationals in the third round of the 2007 Draft, Souza joined the Suns following Friday's 15-2 win over Lakewood. Consecutive rainouts and a day off meant he didn't get to take his first swings in a competitive game until Tuesday. And after going 0-for-5 on his 23rd birthday in the first game of a seven-game road trip, he made up for lost time.
Souza ripped a bases-loaded triple in the first inning, walked in the second and grounded out to shortstop in the third. A two-run single up the middle in the fifth extended Hagerstown's lead to 10-2 and, after flying out in the sixth, he hammered a three-run homer to center field.
"I remember being on deck and watching [Matthew] Skole, who had four walks already. I knew they didn't want to throw to him, so I just wanted to keep it going," he said of his first homer since Sept. 3. "I wanted to fall in line and keep it going. I was just trying to keep it simple and barrel something."
Already with eight RBIs, Souza came to bat with the bases loaded again in the eighth. Reliever Joe Lucas broke Souza's bat with a sinker in on the hands, but the ball hit the shattered barrel near the mound and allowed another run to score.
"I've never had a nine-RBI game," the Washington native said. "I don't remember [my highest], but I will remember this game. The thought of a cycle never even crossed my mind until the last inning.
"I was happy to just be playing again. I had to rehab my knee and change position, but luckily they put me in a great position to succeed here. There was no pressure on me to perform. When you're hitting behind a guy who is batting .373 with 26 RBIs and four home runs, it's pretty easy to hit. It helps when you're in a lineup where you can be hidden."
It was Souza's fourth career four-hit game and bested his previous high of five RBIs, achieved twice before and most recently on April 16, 2010. The career night instantly placed him fifth on the team in RBIs three weeks.
Souza spent last season in the Class A Advanced Carolina League and batted .228 with 11 homers and 56 RBIs in 122 games.
Six Suns starters collected at least three hits and every starter except Cole Leonida -- who struck out a league-record six times -- reached base at least three times. The 24 runs and 24 hits were both five short of the SAL record.
Taylor Hill (3-0) allowed two runs -- one earned -- on five hits over five innings to remain unbeaten, while Nathan Karns gave up two hits and struck out five over the final four frames to earn his first professional save.
Rome starter Carlos Perez (0-3) surrendered seven runs on eight hits and three walks while fanning five over two innings.