Can the Cosmos be beaten?

That is the main question the 15 other playoff teams are asking as the North American Soccer League begins its second season tonight.

The defending league champion Cosmos, who establshed a ton of league records this season, are favored to repeat as National Conference titlists and play the American Conference survivor in Soccer Bowl '78 at Giant Stadium on Aug. 27.

The league, winding up its 11th season, added a new wrinkle to its playoff format this year. A total of 16 teams, instead of 12, were awarded playoff berths, a move designed to add fan excitement and bring a few extra dollars to the players and owners.

The top two teams in each of the three divisions in each conference automatically made the playoffs. The next two teams with the highest number of points also made the playoffs as wild card teams, giving each conference eight teams.

The first round will be a single eliminaion game played under standard NASL rules. The conference semifinals witll consist of a two-game home-and-home playoff series with first-round winners matched acording to points. The team with the most points plays the team with the fewest points and the team with the second-most points meets the team with the third highest number of points. In each matchup, the host for the first game will be the team with the fewest points.

In case each team wins one game by the identical goal differential, a 30-minute sudden death overtime period will be played. If no one scores, the teams will go into a shootout to produce a champion.

The conference championship also will be a two-game home-and-home series, conducted in the same manner as semifinals.

The Soccer Bowl will be a single game, using the standard league rules.

A look at the conference breakdowns: NATIONAL CONFERENCE

The Cosmos (24-6, 212 points) had no trouble winning the Eastern Division. The "Best Team Money Can Buy" fought off an early challenge by the Washington Diplomats and ran off winning streaks of five, five and six during the season. They rewrote almost every offensive record in the book, including the most points and most goals (88).

The Cosmos, who have the home-field advantage for each playoff round, should be at full strength against Seattle (15-15 and 138) in a first-round game tomorrow night.

The rematch of the '77 Soccer Bowl, won by the Cosmos, 2-1, shouldn't be much of a test. Seattle has stumbled along most of the season and needed three victories down the stretch to earn a wild card berth.

The scoring combination of Girogio Chinaglia, the league's record-breaking scoring leader with 34 goals and 11 assists for 79 points. Steve Hunt (35 points), Vladislav Bogicivic (37 points) and Fran Beckenbauer (32 points) should be too much for Seattle's defense and goalie Tony Churcky.

In other first-round games, Portland (20-10, 167) hosts Washington (16-14, 145) and Vancouver (24-6, 199) entertains Toronto (16-14, 144) tomorrow night. Minnesota (17-13, 156) hosts Tulsa (16-14, 141) Thursday night.

Vancouver, winner of its last 13 games, also a NASL mark, appears to be the team in the conference with the best chance to dethrone the Cosmos. Led by Kevin Hector (46 points), Bob Lenarduzzi (33) and Alan Hinton, who had 30 assists this season, the Whitecaps tied the Cosmos for most victories in a season (24). The Whitecaps held opponents to one goal or less in 25 of 30 games.

Vancouver's opponent, Toronto, also has been hot. The Metros, '76 Soccer Bowl winners, won six of their last nine games.

Minnesota, the only team to win a division title three straight seasons, should easily vault past expansion Tulsa.

Washington will be trying to snap a four-game losing streak in Portland. The Timbers bested the Dips, 2-1, on a shootout during the season and have played well the last few weeks. AMERICAN CONFERENCE

The Detroit Express (20-10, 176), the surprise of the NASL, is being touted as the team to advance to the conference title. The first team to clinch a division crown, the supercharged Express won its first three games and ran away from the rest of the conference.

Forwards Trevor Francis, who scored 22 goals in 19 games, and Keith Furphy (34 points) lead the Detroit offense; goalkeeper Steve Hardwick, with 179 saves and nine shutouts, anchors the defense.

Detroit's first-round foe, Philadelphia, which slipped into the playoffs with three victories in the last 10 days, must contain the scoring duo tonight. Francis scored five goals in a 10-0 rout of San Jose and Furphy scored game-winners four times this year [TEXT OMITTED FROM SOURCE] first-round games tonight have San Diego (18-12, 164) hosting California (13-17, 115) and Tampa Bay (18-12, 165) meeting Chicago (12-18, 23). New England (19-11, 165) entertains Fort Lauderdale (16-14, 143) tomorrow night.

Fort Lauderdale must stop New England scorer Mike Flanagan. The striker scored 30 goals despite missing the last 2 1/2 games of the regular season. But Flanagan is over his pulled leg muscle and New England will have to be reckoned with.

The Chicago Sting got off to a miserable 0-10 start before changing coaches and righting themselves. Karl-Heinz Granita, with 19 goals, is the main reason Chicago is in the playoffs. Host Tampa Bay, the veteran team of the playoffs with four straight appearances has the offense led by Rodney Marsh, and the defense, with goalie Winston DuBose, to pull several upsets.

Western Division winner San Diego had little competition in capturing its first crown since 1968. After several rocky years in San Diego, the team folded in '76, played in Las Vegas last year and returned to San Diego to make the playoff this season. With the front line of Walker McCall (29 points), Jean Willrich (28) and Julie Vee (27), the Sockers should have no trouble getting past Western Division runnerup California, an expansion team they defeated twice during the regular season.