"I'm feeling great, my arm feels great right now," Smyly said. "I'm just trying to get my work in, work on my pitches, just go out there and compete and have fun."
Jennings put the Rays on top when he homered with Logan Forsythe aboard in the third off of Pirates starter Francisco Liriano.
Corey Dickerson added an RBI single in the fifth to push the lead to 3-0. The Rays extended the lead to 5-0 when Cameron Seitzer plated two on a sharp single to right field in the bottom of the seventh.
Jennings, who was limited to 28 games in 2015 due to an assortment of injuries, is off to a hot start this spring hitting .500 (5-for-10) with a home run and seven RBIs in five games.
Liriano, who will pitch at the top part of the Pirates' rotation this season, allowed two runs on five hits and a walk while striking out three in three innings. He threw 49 pitches of which 33 were strikes.
"It feels good. Just missed a couple pitches. I think I was rushing a little bit the first couple innings," Liriano said. "You feel too fresh, the body feels great, just trying to overdo things, trying to rush, going forward too quick and not executing pitches."
The Pirates got on the board when Michael Suchy socked a solo shot off of Adam Wilk in the top of the eighth.
Up next for the Pirates: The Pirates will host a rematch with the Rays at McKechnie Field at 1:05 p.m. ET on Friday. The game will air on MLB.TV. Right-hander Juan Nicasio will continue to stretch out his arm as a starting pitcher as he makes his third appearance of the spring. Relievers Mark Melancon and Tony Watson and prospects Steven Brault, Chad Kuhl and Trevor Williams are scheduled to pitch. Andrew McCutchen will start in center field, flanked by Gregory Polanco in right and Starling Marte in left.
Up next for the Rays: Jake Odorizzi will make his third start of the spring when the Rays travel to Bradenton, Fla., to play a rematch with the Pirates in a 1:05 p.m. ET contest to be broadcast on MLB.TV. Also scheduled to see action are right-handers Steve Geltz, Ryan Garton, and Adam Reifer along with left-hander Blake Snell.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.