SEATTLE -- Josh Rojas shared a clubhouse with many of those in the visiting dugout on Friday night at T-Mobile Park, but for Mitch Haniger, it’s been ages since he donned a D-backs uniform. Those two pounded their former team with towering home runs that lifted the Mariners to a 6-1 win over Arizona as Seattle opened a big homestand against the reigning National League champions.

Rojas crushed a 405-foot solo blast off All-Star Zac Gallen on the first pitch in the bottom of the first inning, then Haniger blasted a 389-foot grand slam in the sixth off reliever Scott McGough, shortly after Gallen left with right hamstring tightness. Mitch Garver also hit a sky-high solo blast in the second inning to snap an 0-for-16 skid.

The sluggers’ efforts, coupled with Emerson Hancock’s third straight quality start, continued the Mariners’ momentum on the heels of a big series win at Texas, giving Seattle an early litmus test by facing each of last year’s World Series teams in succession.

The Mariners, who were off to a tough, 6-10 start to the season, advanced to a season-high two games above .500 (14-12) and held onto first place in the American League West.

“The start of the year wasn't what we wanted, and there's a lot to be said on what can be different and all these things,” Haniger said. “And a lot of times you just have to keep coming to work, working hard and not giving in to all the BS and just keep trying to get better.”

Moreover, the Mariners continued to exhibit the type of roster-wide potential that the front office banked on when assembling this group, one built on stringent starting pitching and enough offense to hand the baton to a lights-out bullpen.

The Mariners are now 11-5 when hitting a home run, 13-2 when they receive a quality start and 13-0 when leading after the sixth inning. They can win their fourth straight series on Saturday after going winless in their first five.

“That's how we're built,” Mariners manager Scott Servais said. “We know that. We're at our best when we're pitching like that and getting timely hits.”

Uncharacteristic pitching hiccups contributed to Seattle’s slow start, but the biggest factor in the club’s turnaround has been offense, and particularly via power. The Mariners had a .328 slugging percentage through April 14, fourth-worst in the Majors, when they were a season-low four games under .500. Since then, that number is .440, fifth best.

“We haven't even scratched the surface yet of I think how good we can be offensively,” Servais said.

Haniger had been in a funk on Seattle’s road trip through Colorado and Arlington, going 2-for-21 with 10 strikeouts. Garver has been in one all year, now hitting .143 with a .536 OPS. Yet the Mariners have mostly been able to withstand those struggles thanks to contributions elsewhere, especially Rojas, who’s been the club’s most pleasant surprise and consistent hitter, with a team-best .316 batting average and .391 on-base percentage.

As such, Rojas, who was acquired in the Paul Sewald trade at last year’s Trade Deadline, will also see more time at leadoff, especially against righties, after J.P. Crawford was placed on the injured list on Thursday with a right oblique strain. For a coincidental effect, Rojas threw out the player he replaced -- third baseman Eugenio Suárez -- for Friday’s 27th out.

“Gallen is a guy who I've talked pitching strategy a lot with,” Rojas said. “... So it was kind of a cool experience for me to be on the other side and think, 'All right, I've picked his brain, so let's see what he's going to try to do to me.’”

This lineup also goes as Julio Rodríguez does, and the Mariners’ best player has also turned a corner, with singles of 107.7 mph and 102.7 mph on Friday, marking his seventh multi-hit effort in his past nine games. Rodríguez crushed his first homer of the year on Wednesday, a massive, 435-foot, 110.5 mph shot that’s been part of an overall hard-hit uptick. Seattle is 14-5 when he gets a hit and 0-7 when he’s 0-fer.

But Hancock and the bullpen all deserve merit, with just three hits and four walks combined, the lone run via a homer against Hancock on a sinker low and way inside. Take away an eight-run outing in Milwaukee on April 7, and Hancock has a 2.70 ERA in his other four starts.