ST. PETERSBURG -- Three of the Rays’ most perplexing trends continued in a 4-2 loss to the Mariners on Tuesday night at Tropicana Field.

The Rays were once again shut down by a left-handed starting pitcher, as Yusei Kikuchi limited them to two runs over six innings. They made a few costly mistakes in the field, the kind of errors their sure-handed defense seemed incapable of making in the first half of the season. And they could not beat the Mariners, who have won all six games in their season series heading into Wednesday’s finale.

• Box score

The last part is perhaps most baffling. Tampa Bay is 64-38 against the rest of the league this season and 0-6 against Seattle, which has now won eight of the clubs’ last nine meetings while going 7-1-0 in their season series dating back to 2014.

There might have been two silver linings to Tuesday’s game for the Rays: Their one-game lead in the American League East is intact, as the Red Sox also lost on Tuesday, and they won’t have to see the Mariners again after Wednesday afternoon.

“They've got our number. I don't know what else to say,” Rays manager Kevin Cash said. “It's frustrating losing games, I don't care who it is. And I don't care how many times it's one team, if it's lopsided one way or the other. We're just not playing very good baseball, and they are. We're in a lot of these ballgames, but being in doesn't count. So we've got to find a way to salvage a season series tomorrow.”

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Maybe the good news is that the Rays will face a right-hander, Logan Gilbert, in the series finale. They fell to 24-20 this season against left-handed starters after Tuesday’s loss, a respectable record but a big drop-off from their 40-24 mark against right-handers. Kikuchi held them to only six hits and two walks in six innings, and Tampa Bay finished the night 0-for-4 with runners in scoring position while stranding seven men on base.

The Rays gained their first -- and, so far, only -- lead of the series in the first inning, when Randy Arozarena ripped his second career leadoff home run out to left field off Kikuchi. Wander Franco then smacked a single to left, but Tampa Bay’s hopes for a big inning quickly dissipated as Nelson Cruz smashed a 100.8-mph ball to third baseman Kyle Seager, who started a double play before Yandy Díaz grounded into the last out of the inning.

The Rays have had more at-bats against left-handed pitchers than any other team in the Majors this season -- 1,327, to be exact -- yet they are hitting just .226/.303/.378 as a team against southpaws. They made a concerted effort to improve that by acquiring Cruz on July 22, and they’re hoping their results soon match their hitters’ track records in that department.

“It’s something that I think we can and will get better on as we go later on. We certainly have the players to do it,” infielder Joey Wendle said. “Obviously a pretty good arm [in Kikuchi] tonight. So yeah, it is frustrating, and certainly we'd like to be hitting better off the left-handers.”

The Mariners pulled even in the second, capitalizing on the good fortune they’ve seemed to carry throughout this season’s matchups with the Rays. Jake Fraley hit a bloop double to shallow left, then came around to score after a pair of flyouts. Seattle jumped ahead in the fourth, when Abraham Toro (first-pitch curveball) and Jarred Kelenic (1-0 fastball) hit solo homers off right-hander Luis Patiño.

Patiño couldn’t quite match his last performance, when he worked six scoreless innings with eight strikeouts against the Yankees. The 21-year-old righty allowed three runs on five hits and two walks while striking out only three batters, and he needed 100 pitches to complete five innings.

“I think I threw a lot of good pitches, especially my breaking balls, but give credit to them for fouling it off and fighting it out,” Patiño said through interpreter Manny Navarro. “But this is just an outing that I think I’ve got to learn from, look back on it, kind of study it, learn from it and take it onto the next outing and stay positive.”

Patiño kept Tampa Bay in the game, however, and the Rays cut the Mariners’ lead to one run in the fourth as Austin Meadows singled and scored on a hit by Manuel Margot followed by Fraley’s misplay in left field. That was all they’d manage the rest of the way, however, as they were shut down by Kikuchi and a tough Mariners bullpen, including former teammate Diego Castillo.

Meanwhile, the Mariners took advantage of a few mistakes by the Rays in the sixth to add an insurance run. Lefty reliever Ryan Sherriff allowed a single to Toro, who advanced to second on a wild pitch, took third on an errant throw by Wendle then scored with one out on Cal Raleigh’s fielder’s-choice grounder. Franco fielded the ball hit by Raleigh and made a short, slightly off-target throw to second baseman Brandon Lowe, but the ball bounced off Lowe’s wrist.

The Rays have committed multiple errors on consecutive nights and 15 overall since the All-Star break. That would have seemed out of character a few weeks ago, as Tampa Bay clearly established itself as baseball’s best defensive team in the first half. But the Rays entered Tuesday night with the most errors in the AL in the second half.

“It's been just uncharacteristic. The guys work really hard at the defense,” Cash said. “Generally speaking, we are just so good, tops in baseball all around, position by position. And the last two nights, it's kind of not been at our best.”