PORTLAND, ORE.: When the fourth quarter comes, LeBron James' blood turns cold.

He did it again Wednesday, if you can believe it, to break thousands more hearts in a crazy and hostile environment. Saving his best for the very end, James led another comeback and delivered another dagger.

Sprinting past rival star Brandon Roy, James smacked in a smooth left-handed layup with 0.3 seconds left to get the Cavs to an 84-83 victory in the gulag that is the Rose Garden. And just to make sure the vanquishing was complete, he stole the inbounds pass to finish game.

This time he had 37 points, and 17 of them came in the fourth quarter, including back-to-back 3-pointers that erased a six-point Blazers' lead with three minutes left. He did it despite suffering a turned right ankle and jammed left pinky finger during the game, but there was no limp in the effort.

The Cavs (25-19) have now won 13-of-16 games, including in Dallas, San Antonio, Los Angeles and Portland, where the Blazers had been 18-4. Overall they have won six straight games on the road and made a lot of believers along the way as James' campaign for Most Valuable Player award continues.

It was the 18th time this season the Cavs have won when trailing in the fourth quarter. This time, they were down 11 points with four minutes left and still James was able to carry the team to a win.

''I do what I do,'' James said matter-of-factly afterward. ''I prepare myself to be the best player on the floor every night no matter what building I'm in. My teammates feed off that and I feed off them.''

Before the game, the Portland fans were still buzzing about Sunday when Roy defended Atlanta Hawks star Joe Johnson in the final seconds to lead to a one-point win. When the Cavs arrived in town Tuesday, the sports page of the Oregonian was devoted to the Blazers' 6-0 record in games decided by three points or less.

With all due respect, that was before they'd seen the Cavs and fourth-quarter James. This time, he scored all but one of the Cavs' baskets in the stretch run and he supplemented all of it with 14 rebounds, two steals and two blocks. Besides James, no other Cav scored in double figures and the other nine players who got in the game combined to go 13-of-45.

''LeBron put us on his back tonight,'' Cavs coach Mike Brown said. ''We couldn't make a basket to save our lives but he did what superstars do.''

When the Blazers' Joel Przybilla blocked James twice midway through the fourth and the sellout crowd started dancing, it looked like it was going to be another home win. When Roy got into a defensive stance on James with five seconds left and James with the ball, down by a point, many readied for another close victory.

But . . .

''We know the game isn't over until there's three zeros on the clock,'' James said. ''We are No. 1 in comebacks for a reason.''

Though James was again the conquering hero, the reason the Cavs were in the game was their defense. They held the Blazers (26-19) to just 35 percent shooting and forced them to take lots of jumpers down the stretch. Portland was just 7-of-20 in the fourth and didn't score on its final three possessions.

Roy had 16 points but just five in the second half and he was 1-of-5 shooting in the fourth quarter. LaMarcus Aldridge had 16 points and nine rebounds for Portland but also wasn't effective down the stretch.

Zydrunas Ilgauskas struggled with just seven points and Drew Gooden, getting extended minutes with Anderson Varejao out, had just nine. But they combined for 20 rebounds, Ilgauskas getting 13, and had eight in the fourth to help the Cavs shut down the Blazers.

''I don't know when the turning point happened,'' James said. ''We just rode the wave.''