11/13/2014 10:55 EST | Updated 01/13/2015 05:59 EST

Raptors lose 100-93 to Bulls in battle for Eastern Conference lead

TORONTO - Jonas Valanciunas called it "a cold shower" — a harsh early-season lesson that brought the Toronto Raptors back down to earth Thursday night.

The Raptors dropped a 100-93 decision to the Chicago Bulls in a battle for first place in the Eastern Conference. It was Toronto's first loss in six games, and first loss at home in what's been a feel-good early-season story.

"It's a good experience, coming off the win streak. That's good," Valanciunas said. "Make us regroup and be strong in the next game."

Kyle Lowry scored 20 points to lead the Raptors (7-2), who coughed up the game with a dreadful third quarter. James Johnson was big off the bench, with 16 points, five rebounds, four steals and four blocks.

"The third quarter did us in," said Raptors coach Dwane Casey. "They got us on our heels and we stayed on our heels.

"You know that's the kind of game you're going to have against them. It's a hard game to officiate and it's a hard game to play. But you've got to make a muscle and fight through the physicality, the bumps, the grinds. . . we didn't meet that challenge in the third quarter."

Amir Johnson had 14 points, while Terrence Ross finished with 12 points.

Pau Gasol scored 27 to lead the Bulls (7-2), while Jimmy Butler finished with 21, and Derrick Rose scored 20 before leaving the game with 1:53 left with a left hamstring injury.

"I guess it was cramps in my hamstrings," said Rose, who'd missed most of the previous two seasons with knee injuries. "I think it is minor and they decided to pull me out."

The Raptors led by nine points late in the second quarter, but the Bulls lit it up in third, outscoring Toronto 25-14 in the frame, punctuated with a 27-10 run, to send them into the fourth with a 80-66 lead.

When Joakim Noah fed a wide-open Taj Gibson for a dunk early in the fourth, it put the Bulls up by 16, eliciting groans from the sellout Air Canada Centre crowd of 19,800 that included actor Donald Sutherland and Toronto Maple Leafs forward Phil Kessel.

A running layup by Rose put the Bulls up by 18 with 5:03 to play. Lowry — whose collision with a fan seated courtside left him wiping off remnants of an ice cream sandwich — drained a long jumper with 3:05 to go to make it a 10-point game.

With the fans on their feet, Ross connected on a three to pull Toronto within seven, then a James Johnson block led to an Amir Johnson dunk, and the deficit was five points.

But Mike Dunleavy's two free throws with a minute left put the Bulls back up by seven, then it was a matter of the clock running out on Toronto.

"You find out you really aren't as good. . .," James Johnson said. "But none of us have big heads in here, all of us strive to get better every game regardless of whether we win or lose, we look at film regardless of whether we win or lose, and learn from the mistakes."

The game marked the first time the Raptors hosted a nationally-televised game on TNT since the Raptors hosted Orlando — Vince Carter vs. Tracy McGrady — in 2002. And the Air Canada Centre dressed up for the occasion, unfurling the giant "We the North" banner.

The noise was reminiscent of last season's playoff games, but all the ACC's cheering couldn't lift Toronto to a victory.

Lowry said the game was a good gauge of where the Raptors are at — and where they need to get to.

"Just know that's what we've got to get up to, that physicality, that type of defensive intensity, that type of offence that they could go to a couple of different guys who could take over games at different points," Lowry said.

Toronto's all-star DeMar DeRozan struggled through another uncharacteristically low-scoring night, making just three of 17 shots for 10 points.

"It's fine, I'm not worried about it at all," DeRozan said. "These games, they're going to happen, especially now. I've just got to learn from it, not get down on it, get frustrated. Two years ago, I'd think it was the end of the world, but we're only eight games in. I'd rather have these games now than later on."

It was a strong game for Rose, whose two sprained ankles had kept him out of half of Chicago's games, to this point. Rose played in just 49 games total in the last two seasons, due to knee injuries.

"We have a good team, we had the game up by 10 by then so why force it," Rose said, on the decision to leave the game. "I overstepped, just stretched out a little bit more with my left leg. It just comes with the process I guess of missing two years."

The two teams were evenly matched through a first quarter that saw eight lead changes, and neither team lead by more than three points. The Bulls took a 25-24 lead into the second.

James Johnson scored 12 points in a second quarter that saw the Raptors' second unit contributing 18 of Toronto's 22 points. Greivis Vasquez fed Johnson for a dunk that put the Raptors up by eight midway through the frame, then Patrick Patterson drained a three with 38 seconds to go, and Toronto headed to the dressing room up 52-45 at halftime.

A running dunk by Jonas Valanciunas early in the fourth put Toronto up by five, but then the wheels fell off. Gasol and Dunleavy scored eight points apiece in the quarter to lead a charging Bulls team that took a 14-point lead into the fourth.

The Raptors host Utah on Saturday, then Memphis on Wednesday. Their homestand ends Nov. 21 when they host Milwaukee.

NOTES: The Raptors' last TNT game was April 16, 2013 in Atlanta after an Indiana-Boston game was cancelled due to the Boston marathon bombing. . . The Raptors' previous best start to the season was 4-1 in 2004-05.

Note to readers: This is a corrected story. An earlier version reported that the "We the North" banner had not been unfurled since the playoffs.