Presented with a one-run lead, Looper started the ninth inning by committing the cardinal sin for a reliever, walking the leadoff man in Tino Martinez. Alex Rodriguez followed with a double down the third base line that shot past a diving David Wright.
"You can't walk the leadoff hitter," Looper said. "There's no excuse for that."
"It doesn't help too much," Randolph said.
Now, with runners at second and third and nobody out, the Mets elected to intentionally walk Hideki Matsui -- whom Randolph called the Yankees' best RBI man -- setting up a force at any base.
Looper worked the count to 1-1 against Giambi, but the power-hitting slugger went down and ripped a splitter to the wall in right-center field, plating the tying and winning runs.
"My team had the game won," Looper said. "I basically let them down. We should have won the game."
It was the third blown save of the year for Looper, who did not retire a batter in the outing.
"All people who don't blow a game are gods," said Roberto Hernandez, who got the last two outs of the eighth inning. "We're not in that position."
After starters Kris Benson and Randy Johnson allowed one run each through the first six innings, the Mets took advantage of two Yankees infield errors in the seventh to take a briefly-enjoyed three-run lead.
Robinson Cano wasn't able to handle Marlon Anderson's two-out infield roller, plating a run and chasing Johnson in favor of Tom Gordon, and the Mets involved the veteran reliever immediately. Jose Reyes chopped a grounder to the right side that Giambi flipped poorly to Gordon covering the bag, tipping his throw off the reliever's glove and allowing a pair of additional runs to score.
The Yankees cracked back with two runs in the seventh on RBI hits by Derek Jeter and Rodriguez, but the Mets' bullpen picked up from there into the ninth inning.
Royce Ring got Matsui to ground out to end the frame, preserving the one-run lead, and Hernandez left the bases loaded in the eighth inning, getting Ruben Sierra to fly out to deep left-center.
"I knew if I made my pitch against Ruben, I was going to get out of it," Hernandez said.
Both teams managed just one run through the first six innings, as Benson and Johnson traded zeros for much of the early going. Reyes drove in a run with a groundout facing Johnson in the third inning, and Cano plated the tying run with a fielder's choice in the sixth -- a play on which Anderson made a sensational stab to the right of second base.
With the loss, the Mets finished their 12-game road trip with an 5-7 record and will head back to Shea Stadium, opening a three-game series against the Philadelphia Phillies on Tuesday night.
Even without the sweep, the Mets are able to ride across the Triboro Bridge on plenty of positives, having salvaged a trip that started poorly in Oakland and Seattle by winning two of three at Philadelphia and at Yankee Stadium.
"I'll take these last six days and have a good day off [Monday]," Cliff Floyd said.
"We don't feel down at all," Carlos Beltran added. "In our minds, we won the series. That's important."