Through the early innings at Petco Park, the Mariners kept up with San Diego. Each team was held to one run as both starting pitchers looked locked in. But Seattle’s sub-.200 team batting average couldn’t match the five-run fifth inning San Diego pinned against left-hander Justus Sheffield.

After a 6-4 loss at Petco Park Saturday night, the Mariners have matched a season-high five-game losing streak. Seattle has scored just eight runs total in its last five games, which includes being no-hit Tuesday by Tigers right-hander Spencer Turnbull.

• Box score

After the Padres got on the board with an RBI double in the second, Mitch Haniger clobbered his team-leading 13th home run in the next half inning to tie the game. His Statcast-projected 381-foot long ball to center tied him with Toronto’s Vladimir Guerrero Jr. for fourth on MLB’s home run leaderboard.

The score stayed knotted at 1 until the fifth, when the Padres capitalized on four singles, two walks (one intentional) and three Mariners errors to put up five runs.

The Mariners showed a glimmer of hope in the later innings, prompting San Diego to call on closer Mark Melancon to prevent Seattle from cutting into the lead any further.

"We did some good things, we competed right at the end, got a chance to get the closer up, we got the tying run up there to the plate,” manager Scott Servais said of Seattle’s late effort. “But that's not just enough to get ’er done tonight.”

In the eighth, catcher Jacob Nottingham, who was re-acquired from the Brewers on Thursday, plated Kyle Seager on a sacrifice fly, chipping away at the Padres’ four-run lead.

In the ninth inning, Tom Murphy found himself at third with no outs following a leadoff double and a passed ball. Murphy crossed the plate on Jack Mayfield’s RBI groundout to shortstop Fernado Tatis Jr. After Sam Haggerty was hit by a pitch, San Diego turned the ball over to Melancon, who struck out Jarred Kelenic.

Haggerty advanced to second on defensive indifference and scored on the next pitch as Melancon spiked the throw to first on Hanniger’s soft tapper to the mound. The late rally ended with Kyle Lewis striking out on a checked swing.

"Guys have to stay upbeat, we have a long season ahead of us. We're learning a lot about our team as we go along and part of it is you learn a lot about people when things are not going good,” Servais said. “Our guys are grinding, they're working hard, they're communicating well amongst themselves, with our coaching staff. So, we're going to keep building going forward. It'll turn.”

Seattle is four games under .500 and 6.5 games behind the A’s in the AL West.

Sheffield, who got his first MLB hit, attempted to right the ship for the Mariners by holding the Padres to one run over four innings, but the five-run fifth dented his final line. The southpaw is still looking for his first win on the road this season. Sheffield was tagged for six runs (five earned) in five innings and recorded three strikeouts against five walks, a season-high for him. His sinker accounted for over one-third of his pitch count against the Padres, but he was only able to induce one swing-and-miss on it.

"The goal was to bust these guys in. They are a patiently aggressive team, I guess you could put it, they kind of find the pitch they want and find a spot that they're looking at. When you go up against lineups like that it's really important to pound the zone, and get in on them and make them feel uncomfortable,” Sheffield said. “I threw some good pitches tonight overall, I feel, but definitely could have been better. So, come back the next day, come back tomorrow and go to work and get better.”