Three local football teams remained undefeated last week but the unbeaten ranks dropped by one as Yorktown fell to South Lakes, 14-7. W.T. Woodson and Langley stayed unbeaten in girls tennis and Lake Braddock continued its cross country excellence in the University of Virginia Invitational. Football

Top-ranked T.C. Williams and defending Northern Region champion Marshall both remained unbeaten with impressive victories last week, but Yorktown slipped to 4-1 after a 14-7 loss to South Lakes. Bishop Ireton improved to 5-0 with a 10-0 win over Paul VI. Lopsided scores dominated the results with only two games being decided by one touchdown or less.

T.C. Williams held Edison to 76 yards in total offense as the Eagles were without running back Chad Lewis, out with a knee injury and Sherman Deck played with the flu. The Titans' offense was led by Lydell Scott, who rushed for 105 yards and three touchdowns in a 31-0 romp. Williams has scored at least 28 points in each of its four wins.

Ireton won its first five games for the first time in its history under first-year head coach Jim Hall as Mike Lalli scored on a seven-yard run and the defense was outstanding in a shutout win over Paul VI. In 1974 the Cardinals started out 4-0-1 on the way to a 6-3-1 mark.

Marshall running back Chris Suggs scored on runs of 18 and 53 yards to lead the Statesmen (4-0) to a 29-7 win over McLean. It was the second straight Great Falls District win for the Statesmen.

Linebacker Jeff Hicklin blocked a Yorktown field goal and returned it 80 yards for the go-ahead score in South Lakes' 14-7 win over the Patriots. Yorktown slipped to 1-1 in the Great Falls District, tied with South Lakes (3-1) and Herndon.

In other Great Falls action Herndon (3-1) rolled to a 34-12 win over Washington-Lee. Quarterback Warren Prisby broke loose for a pair of touchdown runs in the Hornets' win. Madison running back B.J. Runyon rushed for three touchdowns and caught a pass for another as the Warhawks' rolled past Langley, 42-7.

Annandale (2-2) opened Potomac District play with 35-0 blanking of Stuart. Julio Lacayo rushed for 123 yards and three touchdowns while the defense's first unit allowed Stuart to cross the 50-yard line just twice. In another district contest Randy Belknap rushed for a pair of scores and Fairfax (3-2) allowed just a fourth-quarter score in routing Falls Church, 35-6.

Mount Vernon (1-3) won its first game of the season, shutting out West Springfield, 17-0. Steve Hardeman and Albert DuBose scored second half touchdowns to break open a 3-0 game.

Lake Braddock evened its mark at 2-2 as Kermit Drake rushed for 133 yards and two scores in a 21-6 win over Hayfield (0-4). Oakton running backs Kevin Barnes and J.P. Foley and quarterback Vance Bartley each scored on short runs as the Cougars also evened their mark with a 21-8 win over Lee (1-4).

Robinson tailback Mike Johnson rushed for 181 yards, pushing his season total to 533 as the Rams (3-1) defeated Chantilly, 17-7. Wakefield (4-1) won its fourth straight game as Randy Lyon passed for 176 yards and two touchdowns in a 12-3 win over Halifax. O'Connell (3-2) lost fullback Jason Palumbo (418 yards in four games) to a broken leg in a 3-0 loss to St. John's.

Girls Tennis

Langley improved its record to 6-0 by defeating previously unbeaten South Lakes, 7-2. It marked the first time this season that Langley did not record a 9-0 shutout. Earlier the defending Great Falls District, Northern Region and AAA State champion, recorded shutout victories over Herndon, Washington-Lee and Yorktown. In defeating Yorktown, number one singles player Allegra Milholland (see profile) came from a 9-6 deficit facing three match points to remain unbeaten with an 11-9 win over Kristina Soderquist.

In Northern District action, W.T. Woodson continued its undefeated season with a 5-4 victory against West Springfield. The Cavaliers are now 7-0.

Cross Country

Lake Braddock continued its dominance of Virginia cross country, winning the boys and girls Cavalier Race at the University of Virginia 5000-Meter Invitational in Charlottesville. Woodbridge finished second in both races. The Bruins' boys won, 64-118, and the girls won, 68-104. Vince Hancock and Brad Baker finished second and fourth, respectively for the Bruins. Golf

Madison avenged last year's Northern Region playoff loss to Langley by beating the Saxons, 160-165, last week. The Warhawks, who were undefeated in Great Falls District play last season, bettered their record to 4-0 in district play and 4-1 overall, losing only to Chantilly, one of the strongest regional contenders.

Chantilly rolled to three district wins to improve its Potomac mark to 5-0. Blair Johnson, who shot a pair of one-over par rounds and an even-par round, leads the team which is 7-0 overall and has one district match remaining.

Field Hockey

Cindy Ritter scored two goals, including the game-winner eight minutes into overtime as Madison defeated Langley, 2-1.