Vazquez also set up Ronald Matarrita, who assisted on both Vazquez goals. The four goals in four games lifted Vazquez into a tie for the league lead.
After Cincinnati (2-2-0, 6 points) halted an MLS-record 14-game losing streak with last weekend's 2-1 win at Orlando City SC, it didn't waste time carrying over that momentum as Vazquez and Matarrita each scored within the first 24 minutes of this contest.
Then, FCC didn't allow Inter Miami (0-3-1, 1 point) to build off Gonzalo Higuain's 30th-minute penalty.
Cincinnati overcame Luciano Acosta's missed penalty shot and exhaled when Vazquez, also responsible for both goals at Orlando, struck in the 82nd minute to secure the outcome and snap a home slide that dated to its 2-0 win over Toronto FC on Sept. 11, 2021.
FCC has now won back-to-back games for the first time since June 2021. This was also Cincinnati's first victory in five tries against Miami, which has struggled since opening with a scoreless draw against Chicago.
Inter totaled 13 shots Saturday, but just two were on target.
In the 18th minute, Vazquez crossed through the box to Matarrita, who blazed a shot into the near corner. Six minutes later, Matarrita returned the favor when he floated the ball into the box, where Vazquez outleaped the Miami defense for a successful header.
However, a lack of defensive discipline from Matarrita allowed Inter Miami to cut into the 2-0 deficit. Matarrita's uncontrolled slide tackle on DeAndre Yedlin in the box gave Miami a penalty kick, and Higuain buried it into the net.
It looked as if FCC would extend its lead when Vazquez was taken out in the box on 76 minutes. However, Acosta's nonchalant approach to his penalty resulted in a wide shot that kept the Miami in the game.
Shortly after, Cincinnati made it 3-1 anyway, when Matarrita and Vazquez teamed up again, with the latter heading home a far-post cross.
Miami played without key defender Brek Shea, who was unavailable due to a red-card suspension.