Boys’ hockey playoffs in Maine begin this week with clear favorites in both classes, as Lewiston looks to run the table in Class A and Greely strives for back-to-back Class B titles.

In a year boasting of parity, Lewiston is the exception. The Blue Devils are 18-0, shooting for a fourth championship in the past five years. They are the first Class A team in 12 years to go through the regular season without a loss or a tie.

Defending Class A champion St. Dominic (14-4) is the second seed, but the Saints have lost twice to Lewiston, 3-0 and 6-0.

No. 3 Scarborough and No. 10 Biddeford/Massabesic/Old Orchard Beach were also swept in two games by the Blue Devils. Both opposing coaches describe Lewiston in similar terms.

Scarborough’s Jacob Brown: “Lewiston just comes at you for 45 minutes. They know how to grind teams down. They are well-coached and don’t make a lot of mistakes … Coach (Jamie) Belleau gets his guys ready each game.”

Biddeford’s Jason Tremblay: “They are one of the more balanced teams I have seen in the last five years.  They have a very good defense, good goaltending and four lines, where most teams have one scoring line and one more.  They can score from all four lines. They are relentless and, on top of being skilled, they are tireless workers.”

But the Blue Devils are not unbeatable.

“I think a team that can be physical, and is strong defensively, could give them a scare,” Tremblay said.

Lewiston has had some close games, including the season-opener when Greely led 1-0 into the third period, before Lewiston won 4-2. Against Falmouth last month, the game was tied 1-1 before Lewiston prevailed 5-2.

Scarborough has been competitive against the Blue Devils, losing 5-1 in December (after trailing 2-1 after two periods), and losing 3-1 three weeks ago.

Brown is not thinking about a rematch, yet.

“We are really just focused on our quarterfinal game,” he said.

Lewiston, St. Dom’s, Scarborough (13-4-1) and No. 4 South Portland/Waynflete/Freeport (11-6-1) all received byes until Saturday’s quarterfinals in Lewiston – in this new Class A system without regions.

Scarborough was cruising this season with a 7-1-1 record, until a three-game losing streak – to Lewiston, St. Dom’s and a 3-2 upset to Cape Elizabeth.

“I think that Cape game made all of the guys realize that if we are going to win games we have to play to our identity – play a fast, hard and disciplined game and make sure we are selfless on the ice,” Brown said. “Our seniors have really set the tone the last six games.”

The Red Storm have won their last six games, including a pair of 3-2 wins over Falmouth.

While the Yachtsmen have played good teams tough, they are only 7-10-1 and the ninth seed (playing at No. 8 Bangor on Tuesday night). That shows the parity in most of Class A. Biddeford expected to have a competitive team, and the Tigers are 4-11-2, playing at No. 7 Edward Little on Tuesday night. A team-wide flu bug slowed the Tigers, as did the quality of opponents.

“We still have hope,” Tremblay said. “We have played EL tough and, if we could win that game, we know that parity has been huge this year … We have very good goaltending and strong team defense, (so) we are looking for an upset.”

IN CLASS B, defending champion Greely (14-3-1) has been atop the South standings most of the year. The Rangers play a tough schedule, and two losses (Lewiston, St. Dom’s) and a tie (Scarborough) came against the three best Class A team. Greely has had one hiccup, a 4-2 loss (including an empty-netter) at Old Town/Orono last month. That defeat, and some close wins (two-goal victories over Gorham, Yarmouth and York) means Greely can’t coast through the playoffs.

Greely gets a bye in the South semifinal and will play Friday night in Lewiston, against the winner of Wednesday’s quarterfinal game between Brunswick and Gorham.

No. 2 Cheverus opened the playoffs on Monday night, beating No. 7 York 7-1. Wyatt Header and Jack Chaput each had two goals and an assist for the Stags, who will play the winner of Tuesday’s quarterfinal between No. 6 Cape Elizabeth and No. 3 Yarmouth.

In Class B North, Old Town/Orono (12-5-1) is seeded second, behind No. 1 Hampden Academy (13-1-4). In the Broncos final two regular-season games, they lost to Camden Hills and tied Messalonskee.