ATLANTA -- It had been a while since the Penguins wound up on the short end of a lopsided game.

As player after player faded from the lineup because of injury or illness, the Penguins kept things together for game after game.

Last night at Philips Arena, things caught up with the Penguins, who fell, 4-1, to the Atlanta Thrashers when they ran into a strong goaltender and a team desperate for a win and motivated by a scary incident involving its best player.

"You could make a case that we don't have enough of our players, but ultimately we've got to find a way to win," Penguins forward Jordan Staal said.

With a win, the Penguins could have passed Philadelphia to move into first place in the Atlantic Division. Other than a 3-0 loss to Tampa Bay, the game in which star center Sidney Crosby got a high ankle sprain, the Penguins had not lost by more than two goals since a 4-0 road loss Dec. 18 against the New York Rangers.

To the Atlanta Thrashers, a team that had lost five games in a row and is desperate to stay in the tight Southeast Division race, the win was big, but seeing All-Star winger Ilya Kovalchuk limp off favoring his right leg early in the second period was of greater immediate concern.

Leading, 2-0, the Thrashers might have had visions of Crosby's injury when Kovalchuk got hurt.

Penguins winger Jarkko Ruutu checked Kovalchuk into the boards at the Atlanta bench. Kovalchuk crumbled to the ice and Thrashers defenseman Steve McCarthy immediately skated over to Ruutu and delivered several punches to the head.

Ruutu was assessed a major kneeing penalty and a game misconduct, making him subject to a possible suspension from the NHL, as well as a fighting penalty. McCarthy got an instigating minor penalty, a fighting major and a 10-minute misconduct.

"He got the puck. I went to pressure him," Ruutu said. "I went to finish my check. He ducked away, and I barely hit him. I didn't change direction. I didn't put my knee out."

Asked if perhaps the penalties were reflective of the two players' respective reputations, Ruutu shrugged.

"Probably," he said. "I got five minutes for fighting. I didn't even throw a punch. I had my gloves on."

Penguins coach Michel Therrien supported Ruutu.

"I did not agree with the call. Let's put it that way," he said. "If Kovalchuk would have stayed there and taken the hit, nothing would have happened."

Kovalchuk scored the Thrashers' second goal in the first period at a time when the Penguins were pressuring goaltender Kari Lehtonen and matching Atlanta in scoring chances.

"He's been our horse all year, and scored that big goal for us," Atlanta coach and general manager Don Waddell said.

Kovalchuck came back briefly and took a full shift on a power play later in the second period before leaving the game for good, but Atlanta was able to finish off the win without him.

Atlanta veteran Bobby Holik opened the scoring at 7:08 of the first period. The Thrashers upped it to 2-0 when Kovalchuk scored while the Penguins' Jeff Taffe was serving a double minor penalty for high-sticking defenseman Garnet Exelby.

It was Kovalchuk's 38th goal but his first in six games.

The Penguins thought they halved Atlanta's lead at 17:50 of the second period, but it was ruled that rookie Nathan Smith directed the puck into the net with his skate.

"I don't know exactly what the rule is, but I was just going to the net and didn't feel I could get it on my backhand so I was just trying to stop it so I could hit it with my stick," Smith said.

Atlanta opened it up in the third period, with Eric Perrin scoring on a shorthanded breakaway at 1:32 and Jim Slater scoring and chasing Conklin for Dany Sabourin at 3:46.

Defenseman Ryan Whitney broke up the shutout for Lehtonen, who stopped 29 of 30 shots, with a tip-in goal at 8:42 of the third period for the Penguins, who were playing their second road game in as many nights while Atlanta was playing its first game since the All-Star break.

"We're a tired team, but we worked hard and that's all we could ask," Therrien said.