DETROIT -- The Tigers had an eight-game winning streak. The starting pitcher had the fifth-lowest ERA in the American League and retired 10 of the first 11 batters he faced Wednesday in relatively routine fashion. The opposing starter had allowed seven runs in his last start and gave up two runs in his first two innings Wednesday.

All the momentum pointed in the Tigers' direction. Then, like the storms that poured on the city all day and into the early evening, it was gone, along with their eight-game winning streak.

"I don't know," Nate Robertson said after the 9-2 loss to the Mariners at Comerica Park. "I felt great early on, my pitches were down, and then I left a couple of pitches up. I didn't get away with anything."

The collapse was sudden, but to Tigers manager Jim Leyland, the threat was always there. Seattle scored seven runs against the Tigers on Tuesday, and though Cha Seung Baek gave up seven runs over 3 2/3 innings in his last outing, the Mariners' 15 runs made sure his struggles didn't cost them.

Once Robertson left his pitches up, Detroit's fortunes finally sank.

Not only was Robertson in command the first time through the M's order, he allowed just one ball in play out of the infield through those first 11 batters. Richie Sexson and Jose Guillen hit a couple of comebackers to the mound in their first at-bats. Robertson reached just one three-ball count in that span.

Robertson really didn't fall behind in counts after that, either, because any mistake pitch ended up in play.

"Sometimes you get away with pitches," Robertson said, "and anything that was up in the zone today, they hit it. They hit it where our guys weren't, and they made it hurt."

The first pitch that truly hurt went to Guillen, 4-for-7 in his career off Robertson entering the night. After back-to-back singles from Raul Ibanez and Sexson, Robertson (3-2) left a first-pitch fastball up in the strike zone. Guillen hit it deep to right for his fourth homer of the season. Two more hits followed before Craig Monroe threw out Kenji Johjima at the plate to halt the rally.

Once Baek retired the side in order in the bottom of the fourth, Seattle's surge resumed in the fifth. Robertson's 0-2 pitch to Ibanez ended up over the plate and went into the right-center-field gap for an RBI double, then Sexson hit the next pitch into the opposite gap, where it rolled to the wall. Adrian Beltre's line-drive double into the left-field corner two batters later finished Robertson's evening.

"Pretty much everything they hit was up or in the middle of the plate," Leyland said. "But everything was up. He started out good, mowing them down and then for whatever reason, as the game went on, he started to get the ball up and obviously they hit it good."

When asked about a reason, Leyland said the long layoff between starts might have had an effect. Robertson last pitched a week ago. With the Tigers off last Thursday and again on Monday, Robertson's turn came up with two extra days of rest.

The last time Baek (1-0) pitched was last Friday at Yankee Stadium, where his teammates overcame New York's five-run first inning by scoring in the next four. Curtis Granderson's home run to start the bottom of the first, the eighth leadoff homer of his career, seemingly forecast a similar fate Wednesday.

For Baek, however, the second time through the order seemed to have the opposite effect as it did on Robertson. After Carlos Guillen tripled leading off the bottom of the second, the native Korean set down 19 of Detroit's next 21 batters. Moreover, Sean Casey's line-drive sacrifice fly that sent Jose Guillen retreating in right was the last hard-hit ball off Baek until Gary Sheffield doubled to deep center field in the ninth.

Baek sent down Granderson, Placido Polanco and Sheffield in order on swinging strikeouts in the sixth. Polanco fanned for just the fifth time this season.

"I think he settled in," said Granderson, whose leadoff homer tied him with Eddie Yost for fourth place in franchise history. "He definitely had his changeup working. He was able to go ahead and get a lot of quick outs, keep his pitch count down so he could stay in the ballgame. By the time he gets two times through [the order], he starts knowing how to get guys out. I think he learned as he kept going, and the momentum stayed in his favor."

That it left the Tigers so suddenly and without much warning made the end of the winning streak feel abrupt.

"Eventually it was [going to end]," Granderson said. "The good thing is, we get a chance to come back tomorrow and hopefully start another one."