Tampa Bay leadoff hitter Desmond Jennings provided Baltimore Orioles left-hander Wei-Yin Chen with a valuable lesson: The lineups in the AL East can be treacherous from top to bottom.

Jennings hadn't homered in 42 spring at-bats before facing Chen, but he collected a solo shot and grand slam in his first two trips to the plate and added a solo shot off reliever Kevin Gregg in the seventh to carry the Rays to an 8-5victory over the Orioles on Sunday.

Jennings, who began the day with one RBI, had six against the Orioles.

"I felt good from the first at-bat," Jennings said. "I felt like I was seeing the ball good and I was swinging at good pitches today. ... I was swinging at pitches in the zone and hitting them on the barrel and I was getting to pitches inside. That's a good sign for me. So hopefully I can keep that up."

Signed as a free agent after a successful career in Japan, Chen previously started against the Toronto Blue Jays and Boston Red Sox this spring. Orioles manager Buck Showalter hasn't hid him against division opponents, and Chen had no place to hide on Sunday.

Evan Longoria also homered leading off the fifth, his second in two days. Chen allowed seven runs, three earned, and six hits in five innings. All four runs on the grand slam were unearned after shortstop J.J. Hardy's error with one out.

Chen walked two batters and struck out none. He threw 82 pitches, 54 for strikes.

"They're a great team," Chen said through his interpreter. "They have great hitters and they hit me well on my fastball."

Jennings belted a tape-measure shot off Chen in the third inning to give the Rays a 2-1 lead, and he wasn't cheated on his next blast, either. He launched a shot to left with two outs in the fourth after the Rays loaded the bases on Jose Molina's double, a walk to Matt Joyce and Hardy's error.

Reid Brignac popped up before Jennings worked the count full and unloaded on Chen.

Hardy hit a bases-empty homer off Rays starter James Shields in the bottom of the first to tie the score after the Rays took an early lead with back-to-back two-out doubles by Longoria and Jeff Keppinger.

Later in the game, Hardy, Nick Johnson and Nick Markakis hit solo homers off reliever Matt Torra.

Shields, the Rays' opening day starter, allowed one run and two hits in four innings, with one walk and six strikeouts.

Shields had allowed only one run and seven hits in his first three starts spanning 12 innings before allowing three earned runs (five total) and 10 hits over 5 2-3 innings against the Pirates on March 22.

Showalter still hasn't selected an opening day starter. The candidates are believed to be Jake Arrieta and Tommy Hunter. Arrieta started against the Pirates on Saturday and allowed six runs and eight hits in five innings. Hunter threw 90 pitches Sunday in a minor league game.

Chen could be slotted as the No. 2 or No. 3 starter in his first season pitching in the U.S. He's definitely in the rotation. It's just a question of where he fits into it.

Chen made his fifth Grapefruit League appearance on Sunday. In his previous start, he faced 26 batters and gave up three earned runs in a minor league game.

Chen's actually had been better against major league hitters. He held the Minnesota Twins to one run over five innings on March 22, and was 2-1 with a 3.00 ERA, two walks and nine strikeouts in 15 exhibition innings.

Sunday's game didn't offer the same encouragement, but Chen noted that he's doing some experimenting with pitching coach Rick Adair.

"I'm working on my off-speed pitch, my changeup a lot and also my timing is important for me right now, so I'm still working on my timing and delivery," he said.

"This is still spring training and I felt good today actually. This is just part of the game. I felt good, really good."

NOTES: Orioles reliever Matt Lindstrom started a Triple-A game at the minor league complex Sunday morning and retired all four batters he faced in the first inning. Lindstrom said he didn't feel any discomfort in his right leg. He's been dealing with a sore hamstring. ... Orioles LHP Brian Matusz will start Wednesday's exhibition game against Triple-A Norfolk. He's scheduled to go five innings. ... Before Sunday's game, the Rays had scored only 94 runs, second-fewest in the majors behind the Marlins (75). ... The Rays assigned infielder Tim Beckham, the first-overall pick in the 2008 First-Year Player Draft, to Triple-A Durham.