Only Denard Span's fourth-inning roller through the right side kept Hernandez from chasing history.
Hernandez (3-1) struck out nine and walked two. In his past four outings, Hernandez has allowed 15 hits and two earned runs in 31 innings with 32 strikeouts. His ERA dropped to 1.89.
"I was commanding my fastball for a strike, and after that, my secondary pitches were way better," Hernandez said.
He pitched seven 1-2-3 innings and gave way to Delabar for a perfect ninth after throwing 107 pitches.
"Just vintage Felix," Mariners manager Eric Wedge said. "The way he moved his fastball around, dropping his breaking ball and slider in there, used his changeup effectively. Mixing his pitches and working ahead for the most part."
There have been 13 one-hitters in Mariners history, 10 thrown by one pitcher and three combined.
The most recent Mariners' one-hitter thrown by one pitcher was by Jarrod Washburn on July 6, 2009.
Being dominated by the opposing pitcher was not new for the struggling Twins.
Anaheim starter Jered Weaver threw a no-hitter against Minnesota on Wednesday. Saturday, it was little better.
"You go through spells in a season like this," Minnesota acting manager Scott Ullger said. "Hitting is contagious and lack of hitting is contagious."
Jason Marquis (2-1) threw six innings, allowed two runs, four hits and tied a career high with six walks for the Twins.
Three double plays helped Marquis limit the Mariners offense.
But Kyle Seager's two-run single in the sixth gave Seattle the lead. Seager went 2 for 4, including his fourth home run, and drove in four for the second time in four days. He has nine RBIs in his past four games and leads the team with 16 RBIs.
The Mariners loaded the bases in the seventh on two walks and a bunt single by Michael Saunders. A sacrifice fly to left field by Brendan Ryan scored pinch-runner Casper Wells to push Seattle in front 3-0.
Ichiro tripled into the right-center field gap to score Dustin Ackley and Saunders. Seager followed with his homer to right field off Gray, who took over for Maloney.
Gray played for the Mariners last season, which gave Seager strong knowledge of his repertoire.
The seven runs scored by Seattle on Saturday were one more than it totaled in Hernandez's past three outings.
"Awesome, awesome, awesome," Hernandez said of the run support.
The Twins loaded the bases against Hernandez in the fourth inning. Span singled and went to second on a sacrifice bunt. After Joe Mauer grounded out, Hernandez walked Josh Willingham and Ryan Doumit to load the bases. Hernandez escaped the jam when he got Chris Parmelee to fly out.
Marquis walked Saunders and Ackley to open the bottom of the third. But Ryan failed to bunt the runners over and eventually struck out. Then Ichiro ended the inning by grounding into a 4-6-3 double play.
Minnesota's offense took another hit when Justin Morneau continued to experience pain in his right wrist Saturday.
Morneau had surgery on the wrist in October. The Twins will place Morneau on the 15-day disabled list Monday, retroactive to May 1. Brian Dozier will be called up from Triple-A Rochester to replace Morneau on the roster.
A day after being claimed off waivers from the St. Louis Cardinals, Erik Komatsu started in right field and hit eighth for the Twins. ... Coming into Saturday, Seattle catcher Jesus Montero was hitting .469 in the nine games he has caught. ... Friday's win by Minnesota was the first time the Twins won this season (1-12) when being outhit by their opponent.