Hartford - UConn exhibited its trademark championship heart at the start Monday.

Then top-ranked Louisville, a seriously talented national championship contender, ripped that heart out.

The Huskies completely lost their pulse, crumbling under a smothering defense.

The end result: UConn suffered its worst loss this season, 73-58, in a Big East Conference game before 14,287 XL Center fans.

"We left all our passion in the locker room," junior Shabazz Napier said. "We didn't come out to play in the second half."

This defeat falls in the category of just losing to a vastly superior opponent. Plain and simple, the Cardinals (16-1, 4-0) are a terrific team. They tied a school record for the best start in the program's history and extended their winning streak to 11 straight.

"You're not going to play a better team than that," said freshman Omar Calhoun who scored a team-high 20 points as one of UConn's bright spots.

Louisville weathered the first half playing all but four minutes without Big East preseason Peyton Siva, who sat with foul trouble. UConn had the score (34-28) and raucous crowd on its side heading into halftime. At one point, the Huskies led 29-19.

When Siva rejoined his talented and speedy backcourt partner Russ Smith (game-high 23 points) in the second half, Louisville quickly silenced the Huskies and the crowd. UConn was outscored 45-24, went just 7-for-27 from the field and had 10 of its 17 turnovers after halftime.

"We did a good job of weathering a Peyton Siva storm with him out," Louisville coach Rick Pitino said. "Once he came back, we played much better defense and much better offense."

Louisville scored easy baskets, converting 17 of 28 field goals in the final 20 minutes, and didn't give up any easy points. Siva and Smith carved up the defense with dribble penetration.

The Cardinals picked up the energy and applied their press. The Huskies responded poorly. The dynamic backcourt duo of Napier and Ryan Boatright couldn't lift their teammates out of the Grand-Canyon sized rut. The inside presence of 6-foot-11 Gorgui Dieng (6 points, 16 rebounds, 2 blocks) discouraged the Huskies from attacking inside.

"They played very, very hard in the second half," UConn coach Kevin Ollie said of Louisville. "They took it to us. ... There were a lot of layups. We didn't get back on defense. We didn't play with the force that we were playing with in the first half, with the intensity were playing with on the defensive end."

And UConn (12-4, 2-2) paid dearly for its lapses on the way to losing for the first time at home this season.

Sophomore Chane Behanan's three-point play pushed Louisville ahead for good 42-41 with 15 minutes left and UConn never recovered. His points were part of a 32-10 run to open the second half.

The Huskies, who shot 39.6 percent overall, also struggled mightily in the half-court against an active, alert and aggressive zone. When Boatright's 3-pointer finally ended a nine minute drought without a field goal, UConn trailed 60-47 with 6:44 remaining.

"We weren't able to get to the middle of the zone where we were creating our offense most of the time," Napier said.

After scoring 10 points in the first 7:37, Napier had just two free throws the rest of the way. Boatright had a quiet six points after halftime and finished with five turnovers.

Louisville's game plan to neutralize UConn's two leading scorers worked to perfection.

"We just tried to contain them," Siva said. "They're one of the best backcourts in the nation."

The Huskies fell to 2-7 when playing against the top-ranked team. Now they look to regroup for Saturday's game at Pittsburgh.

"We're going to get better," Ollie said. "I want to praise Louisville; they came out with a great effort. But our guys didn't respond when (Louisville) came out and had that run."

g.keefe@theday.com