One half of the WPIAL Class AA girls doubles tennis semifinals has Butler County written all over it.

The Mars duo of Katrina Erdahl and Christie Hansen will battle Knoch's Chelsea Gibson and Tiffany Allen at 2 p.m. today at Knoch High School.

Both teams are guaranteed a spot in the upcoming WPIAL finals, but today's match will determine which gets a higher seed entering that competition.

The teams earned a spot in the semifinals with their performances at the section doubles tournament Monday afternoon at Lakevue Raquet Club.

Erdahl and Hansen made easy work of Highlands' Deanna Mazur and Kelsey Magee, blanking the duo 10-0 in the first round.

The Mars team then disposed of Vincentian's Andrea Graham and Melissa Spicer 6-1, 6-1.

Gibson and Allen also had an easy first-round affair, defeating Tessa Byford and Nicole Englert of St. Joseph's by a tally of 10-1.

The duo's quarterfinal match was more difficult, but they managed to win two tie-breakers in a 7-6, 7-6 victory over Highlands' Brianna Berenson and Sarah Mark.

Following are the complete results for Mars and Knoch at Lakevue Monday:

First RoundChelsea Gibson-Tiffany Allen (Knoch) def. Tessa Byford-Nicole Englert (St. Joseph's) 10-1; Brianna Berenson-Sarah Mark (Highlands) def. Staci Moeller-Brooke Barnes (Mars) 10-5; Katrina Erdahl-Christie Hansen (Mars) def. Deanna Mazur-Kelsey Magee (Highlands)

QuarterfinalsChelsea Gibson-Tiffany Allen (Knoch) def. Brianna Berenson-Sarah Mark (Highlands) 7-6, 7-6; Katrina Erdahl-Christie Hansen (Mars) def. Andrea Graham-Melissa Spicer (Vincentian) 6-1, 6-1

Butler's Collin Randall (80) and Seneca Valley's Kevin Day (81) and Wes Roberts (79) all qualified for the WPIAL boys golf semifinals with their performances Monday at the Section 3, Division I competition at Pittsburgh North Golf Course. They move on to compete at Beaver Lakes Golf Course in Aliquippa.At the Section 8 event, held Monday at Rittswood Golf Course, Knoch advanced Joe Sopcisak (81), Rob Gillespie (83) and John Hook (84), while Mars' Jeff Baur (84) also made the cut.The above golfers will next compete at Oakview Golf Club Monday.In Butler's 198-213 win over Sewickley Academy on Friday, Collin Randall tied teammate Nick Blymiller's team-record of 33 at Butler Country Club.Mars' Marissa Glew shot an 88 to finish second and sister Lauren Glew fired a 92 to place fourth at the WPIAL girls golf section qualifier at Beaver Lakes Country Club Monday.Butler golfer Shayla Benninger, the only girl on the Golden Tornado boys teams, shot a 97 in the qualifier to advance.All three golfers qualified for the WPIAL championship tournament, which will be held Oct. 11 at the Club at Nevillewood.

Kelly Berry had 12 kills and Meghan Kosar added eight to lead Mars (7-1) to a 25-11, 25-12, 25-11 win over North Hills.<B>Laurel 3, Moniteau 1</B> - Randi Campbell had 10 digs and Cassie Wiest had four kills for the Warriors.Haley McFeaters added five kills and three aces for Moniteau (3-4).The Warriors won the JV match 2-0.

Dan Thuronyi and Mark Ferguson each scored two goals to lead Karns City to a 6-2 win over West Shamokin Monday.Andrew Harmon and Cory Terwilliger also scored for the Gremlins (9-1).

Jence Rhoads scored her fourth goal of the game three minutes into overtime to lead Slippery Rock to a 6-5 win over Hickory.Rhoads also had an assist.Emma Walter and Elissa McCune also scored goals for the Rockets (8-4, 5-0).Kirsten Weghorst added two assists for Slippery Rock.<B>Fairview 5, Karns City 3</B> - Despite two goals from Brittni Grenninger and two assists from Nikki McElroy, the Gremlins fell in a road game at Fairview.Karns City (8-2) also received a goal from Kristen Barnhart.