Toronto Raptors centre Jermaine O'Neal calls Sunday's game in Charlotte a must win. (Tony Dejak/Associated Press)

It's still too early to push the panic button, of course, but there is no denying the sense of urgency in the Toronto Raptors camp.

After beginning the season with three consecutive wins, Toronto has lost two in a row, including a 110-92 decision to Atlanta Friday night, the opener of a three-game road swing for the Raptors.

Toronto will try to get back on track with a win in Charlotte against the Bobcats Sunday (CBC, 1 p.m. ET), in a game that centre Jermaine O'Neal believes is a must win for the Raptors.

"There is no way we should lose three in a row," he told the Globe and Mail. "We have to win in Charlotte."

Why the concern?

Maybe it's because Toronto looked defensively inept in its last two outings.

After being comfortably handled by Detroit in a 100-93 loss on Wednesday, the Raptors looked lethargic in Atlanta, as the Hawks hit open shots all night and led the game from beginning to end.

Toronto allowed Atlanta to shoot a whopping 54.3 per cent from the floor and drain 12 three-pointers, a clear indication that the team has to start playing better on the defensive end.

"We scored enough points, we just didn't get any stops," Raptors coach Sam Mitchell told the Globe. "Our perimeter defence has to get better. We have to take the challenge to get into people and keep people out of the paint … We just didn't do a good job guarding."

Lineup changes in cards

Don't be surprised if Mitchell juggles his starting lineup Sunday afternoon in Charlotte and decides to have shooting guard Anthony Parker watch from the bench.

Parker is off to a slow start to the season, as he is shooting 38.8 per cent from the floor and managed only 13 points in his last two games.

If he doesn't start, expect Jason Kapono, who scored 14 points against the Hawks, to take his place.

Charlotte and Toronto split their four-game series last season.

The Raptors conclude their three-game road trip Monday night in Boston, before returning home to host Philadelphia.