CINCINNATI -- It began with a leadoff walk from Justin Topa, continued with a single that sent the tying run to the plate then culminated with a game-tying three-run blast in the bottom of the eighth inning. In one swing, pinch-hitter Nick Martini tagged Topa for more earned runs than he’d surrendered in his previous 29 outings combined.

That put the Mariners’ hopes in peril on Tuesday night at Great American Ball Park and sent them on their way to a 7-6 loss after Andrés Muñoz surrendered an infield single to Elly De La Cruz to lead off the ninth inning.

De La Cruz then stole second base and scored easily on an RBI knock from Christian Encarnacion-Strand to sink Seattle to its fourth loss in five games halfway through this East Coast road trip. The Mariners are now on only their second three-game losing streak since the start of July.

• Games remaining: at CIN (1), at TB (4), vs. LAA (3), vs. LAD (3), at OAK (3), at TEX (3), vs. HOU (3), vs. TEX (4).
• Standings update: The Mariners (77-61) are one game behind the Astros (79-61) for the AL West lead, with the Rangers (76-62) one game behind Seattle. The Mariners are in the second Wild Card position, a half-game ahead of the Blue Jays (77-62), with Texas a half-game behind Toronto for the final spot.

The Mariners had hope in the ninth, after a challenge from manager Scott Servais turned a would-be inning-ending double play into a fielder’s choice from Ty France, which was followed by a hit-by-pitch to Mike Ford’s knee. But Eugenio Suárez got too far under a fastball on the outer half in a 3-0 count to fly out and halt the rally, shouting at himself after missing the chance to drive in a go-ahead run in his return to the ballpark that on Monday he had called “home.”

On a night when Seattle slugged three homers, including two from red-hot Julio Rodríguez, its bullpen’s challenges on this road trip came to the forefront -- playing into a tough team-wide stretch for the pitching staff after its record-setting August.

“You don't want to be out there with guys on base, especially when you get ahead there early and then kind of let things go on for a little bit,” Topa said. “My slider felt all right in the 'pen, and then I kind of just sprayed it a little bit there. And obviously, that walk is not ideal in that situation.”

Also in the postseason race, Cincinnati leads MLB with 44 come-from-behind wins, and it had the one player on base that the Mariners wanted to avoid.

On a chopping grounder to J.P. Crawford, De La Cruz raced to first in just 4.09 seconds with a sprint speed of 32.0 feet per second, well above the league average of 27.0. He then surged in to steal second with a 29.1 feet-per-second sprint speed with no hesitation despite having been thrown out by Cal Raleigh in the second inning.

“Those guys are going to try to get me out, but they don't have a chance,” De La Cruz said through an interpreter. “I'm going home anyway. ... It doesn't matter if they get me out 20 million times, I'm still going to be aggressive any time I go out there.”

Topa and Muñoz were on the mound in the highest-leverage moments, but the bullpen’s hiccups started in the sixth, when Dominic Leone surrendered solo homers to Encarnacion-Strand and former top Mariners prospect Noelvi Marte to make it a two-run game.

One day after allowing 10 baserunners sans a hit in a losing effort, the Mariners had eight such instances on Tuesday -- via five walks and three hit batters, all three of which came from starter Bryce Miller on breaking balls landing on the back foot of lefties Jake Fraley (twice) and TJ Friedl.

“Ultimately, it comes down to, for me tonight, the free bases again,” Servais said. “The walks, the hit-by-pitches and you kind of keep giving them a chance. ... We usually lock that game down, but we gave them an opportunity to get back in that game.”

Seattle’s relievers have surrendered 12 earned runs, including six homers, in 16 1/3 innings over the past five games for a 6.61 ERA, and the Mets and Reds have slashed .309/.405/.618 (1.023 OPS) in this stretch.

Because it’s September and the Mariners are in the thick of a pennant race, the impact of these games is far more magnified -- even if the sample size is small. Two of their losses on this trip have been by one run.

Miller grinded through five innings and escaped a bases-loaded jam in the fifth to end his outing with only one run. Both he and fellow rookie Bryan Woo are working on career-high workloads, so they will continue to be monitored closely. But the Mariners will also need length down the stretch to keep the bullpen fresh.