Redbirds starter Nick Additon (1-3) had only allowed one hit going into the seventh inning when Lopez turned on a 3-1 pitch, sending it deep over the left field wall.
Additon went six innings, giving up one run on two hits while striking out five in the defeat.
Bryan Petersen added an insurance run in the eighth with a towering home run into the right field corner off Redbirds reliever Cory Rauschenberger. Petersen went 2-for-4 on the night.
Zephyrs starter Elih Villanueva continued his success against the Redbirds by pitching six scoreless innings, giving up no runs on four hits while striking out four, lowering his ERA to 0.94 in 18 2/3 innings against Memphis in 2011.
Dustin Richardson (3-1) picked up the victory by pitching two scoreless innings of relief, getting out a bases loaded jam in eighth.
Jim Rapoport led off the top of the eighth with a triple, but Richardson fanned Pete Kozma. Andrew Brown then hit a one-hopper to Zephyrs shortstop Jesus Merchan, who threw home to nail Rapoport attempting to score.
After a single by Nick Stavinoha and a walk to Freddie Bynum, Richardson got Bryan Anderson to fly out to left to end the threat.
The Redbirds finished 0-for-12 with runners in scoring position, stranding 10 baserunners.
Jose Ceda earned his league-leading 17th save by shutting down the Redbirds in the ninth.
The Zephyrs notched their PCL-high seventh shutout victory.
New Orleans returns to action Friday night at 7 p.m. at Zephyr Field for game two of the four-game series against the Memphis Redbirds. Mariano Gomez (0-1) takes the mound for the Z's as he goes against Adam Ottavino (2-4).