This is the week for final exams in most Maine high schools. The biggest tests for four dozen students on Thursday, however, will involve tennis rackets instead of No. 2 pencils.

Their subject?

Chemistry.

How well doubles partners support each other during inevitable rough patches can mean the difference between season’s end and a berth in Saturday’s state championship matches.

“It can be a little more comforting to have that other player if you’re not playing well,” said Cape Elizabeth junior Conner Sullivan, who teamed with senior Jack Tierney to win the Western Maine Conference doubles tournament last month. “Whomever we play, we never get angry or frustrated with each other.”

Sullivan played third singles last week in a quarterfinal victory over No. 8 Fryeburg, but he’ll be back with Tierney at second doubles when the top-seeded Capers face No. 3 Yarmouth Thursday afternoon in one of six regional tennis finals. A threatening weather forecast prompted organizers to move the matches from outdoors at Bates College to The Racket & Fitness Center in Portland.

Morning matches begin at 9:15 and feature four unbeaten Class A teams. The top-seeded Portland girls and Deering boys take on No. 2 Falmouth. Falmouth’s formidable singles lineup means that any hope of an upset likely will require a doubles sweep from the Southern Maine Activities Association champions.

Western Class C finals pit defending state champion Waynflete – whose boys are seeded fifth and girls third – against the No. 7 North Yarmouth Academy boys and the No. 4 Winthrop girls. Those matches are scheduled for 12:45 p.m.

“I love doubles,” said Cape Elizabeth Coach Andy Strout. “There’s so much more of a strategy to it. So many little things you can help them with to become better.”

Cape Elizabeth, the defending Class B state champ, is scheduled to begin at 4:15 p.m., the same time the top-seeded Greely girls take on No. 6 Spruce Mountain. All four Cape Elizabeth doubles players will be making their finals debut.

“Mr. Strout does a really good job of incorporating the kids who aren’t in the top seven throughout the season, so I’ve had match experience for the last three years,” said senior Jack Hall, who teams with junior Ethan Murphy at first doubles. “He invites us all up to the playoffs, so getting a taste of that last year on the state championship run was really helpful and made the transition easier.”

Hall and Murphy co-captained the Cape Elizabeth basketball team this winter. Their familiarity and friendship comes through on the tennis court.

“Jack and I are working together to win,” Murphy said. “When one of us gets flustered or we hit a few bad shots in a row, the other can come up and calm us down and get us back on track. In singles, you don’t have anybody to set you straight.”

In a testament to the depth of both programs, the second doubles teams from Cape Elizabeth and Falmouth met in the WMC finals, having each knocked off the other’s No. 1 team. Tierney and Sullivan prevailed for the title, 6-2, 0-6, 6-4, over Falmouth seniors Russell Barnard and Matt Hutcheons, who have since moved up to No. 1.

In regular-season matches, Cape Elizabeth swept doubles in Falmouth and Falmouth returned the favor in Cape Elizabeth. In each case, Falmouth swept singles.

“Ideally,” said Falmouth Coach Bob McCully, “you want one brick wall who gets everything back and one who puts it away if given the opportunity.”

Opportunities for advancement are available, and may depend on whose duos are most dynamic.