After an embarrassing start in which Minnesota United allowed 18 goals in its first four matches, the Loons have given up just one goal in the past three.

What has improved to make this about-face possible? Defender Brent Kallman has a simple answer.

"Everything," the center-back said.

While there's a few more specifics that have gone into its defensive reversal, United (3-5-2) will need every bit of that "everything" to be in working order for its match at 2 p.m. Saturday at Toronto FC.

Toronto (6-1-4) just missed out on the MLS Cup last season and currently tops the Eastern Conference and the league overall.

Or, as holding midfielder Sam Cronin called the Canadian side United's "biggest challenge yet."

"Just given the form that they're in and the players they have on the field and being at Toronto, I'd probably say that's safe to say," Cronin said. "[Sebastian] Giovinco and Jozy [Altidore] score practically every time they step on the field it feels like right now. So if we can keep those two off the score sheet, we'll have a great chance. But that's a tall task."

Cronin and left back Marc Burch have bolstered United's defense in the past five matches since the Loons acquired them in a transaction with the Colorado Rapids in late March. Burch, Kallman and goalkeeper Bobby Shuttleworth are three changes to the defense after the Loons' first two matches in which the team conceded a stunning 11 goals.

Coach Adrian Heath said those personnel changes have made a big impact. But he said the whole team, including the attacking players, has become better at defending.

"We have a better grasp of what we're trying to do to defend the goal in general," Heath said. "I don't think there ever is one particular reason why it's gotten better, but it has. But it is mainly down to the collective."

Heath has particularly praised Kallman and fellow center back Francisco Calvo as a strong pairing in the central defense. Kallman said his partnership with Calvo develops more every week.

"We work well because I'm more conservative a little bit, and he's more aggressive," Kallman said. "So we kind of have a nice balance there where one steps out, the other one covers."

With the starting lineup being largely unchanged in the past several matches, Cronin said that familiarity is helping the teammates play alongside each other.

"We're more solid. We're for sure defending the box way better," Cronin said. "It's been a focal point, obviously, just given the start of the season. Too many times, opposing players were just free with time and space in the box, and there are too many good attacking players in the league to do that.

"We're latching on to guys much better. I think we're becoming just a more cohesive defensive unit. Just kind of unspoken communication is developing, too, which is good."

But Kallman recognizes there is another element to United's recent defensive success that, hopefully for the Loons, will also come into play against Toronto.

"I think a little bit of luck as well," he said."