Mariners third baseman Adrian Beltre's one-out single in the seventh ended Cahill's bid for history.
Former Oakland designated hitter Mike Sweeney's strangely sailing double ended the shutout.
And although A's DH Jack Cust capped a nine-pitch at-bat that dripped with drama -- two on, two out, bottom of the ninth -- by smoking a ball into left field, the line drive ended the game.
Cust's rocket was run down by Ronny Cedeno, giving Seattle a 1-0 victory and a three-game sweep at Oakland-Alameda County Coliseum.
The losing pitcher? Cahill, of course.
Further evidence that baseball can be meaner than a baby-sitting big brother with a penchant for banana-based wet willies.
Cahill survived a somewhat spotty first few innings -- three walks and a hit batter through three -- before settling in and giving the home fans more than enough reason to believe that he'll live up to the lofty expectations with which he's been saddled. He used his biting sinker to sensational effect, as only three of the 18 outs he recorded before the seventh were hit in the air.
"Last year when I was the Oakland, I heard a lot about Trevor Cahill," Sweeney said. "Everyone said he was a 'poor man's Brandon Webb,' and he came out today and pitched like it. He pitched really well. [The hype is] not propaganda. When he needed an out, he went to his sinker, and he had tremendous movement on it.
"That's what made him so unhittable. He's going to be good. He's not going to light up a radar gun and throw 97-98 [mph], but he knows what he's doing out there."
Unfortunately for Cahill, he had the misfortune of being matched up with Seattle southpaw Erik Bedard. Every bit as good as his young counterpart, Bedard retired 13 in a row after a two-out walk in the fourth inning and earned the win with 8 1/3 innings of three-hit work.
One of the better pitchers in the American League with Baltimore a few years ago, Bedard had the A's off-balance all day, never falling into any discernible pattern.
"He wasn't really overpowering; he was at 91-92 [mph] most of the day," A's manager Bob Geren said. "But he really had pinpoint command, inside and out. It was a masterful performance by both guys."
Because Oakland got a single from Rajai Davis in the third inning, Bedard's performance was almost an afterthought while Cahill was working on the no-no. Cahill didn't overlook what his opposite was doing, though. In fact, Cahill said he didn't know he was throwing a no-hitter until he looked up at the scoreboard in the fifth inning to see how many hits Bedard had allowed to that point.
"I thought, 'He's throwing a good game,'" Cahill said. "Then I saw that I had a zero [in the hits column]."
There were all sort of eggs on the board for Easter Sunday, but Beltre turned one into a "1" by punching an outside sinker into right field after Ken Griffey Jr. popped out to open the seventh.
Sweeney changed another with a line drive to center field that Geren is convinced took a left turn along the way.
"It was very unusual," said the skipper.
Cahill agreed, adding, "I figured it would fall in, and then it just shot to the left. I've never seen a ball do that before."
Center fielder Davis stumbled while chasing it. It rolled to the wall, and Beltre scored to set up the bottom of the ninth. After a leadoff single by Ryan Sweeney, Orlando Cabrera dropped down a sacrifice bunt, prompting Mariners manager Don Wakamatsu to call on righty David Aardsma.
After striking out Jason Giambi and walking Matt Holliday, Aardsma got a heck of a battle from Cust, who fouled off five pitches before his full-count bolt to left.
"Any time you see that many pitches, you have a better chance of squaring the ball up," Cust said. "And he threw me a lot of fastballs [Friday night], so I know what he's going to come with. I put the good part of the bat on it.
"It just didn't find a hole."
Mychael Urban is a national writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.