On Saturday, when the Washington Capitals played in Montreal, the entire first sports page of the Montreal Gazette was devoted to a story on the New York Islanders. Tonight, as eight other teams begin the Stanly Cup playoffs, hockey fans aready are looking ahead to a Montreal-Islanders final.

Should it work out that way, the Canadians, for the first time since 1975, will be participating in a playoff series in which they do not have home-ice advantage. The Islanders took that away Sunday by defeating the New York Rangers, 5-2, while the Canadiens were stumbling in Detroit, 1-8. The results left the Islanders with 116 points, Montreal 115.

In 1975, the finish was even closer, with Philadelphia, Buffalor and Montreal completing the regular season with 113 points each. The Canadiens were ranked third and lost to the Sabres in the semifinals.

In addition to that home-ice edge in a prospective final showdown, the Islanders earned a likely quarterfinal matchup with Chicago. That figures to be a nice tuneup; while the Canadiens must play a more respectable opponent. The Islanders, Montreal, Boston and Chicago as division winners received byes into the quarterfinals, which start Monday.

All playoff pairings are made on the basis of regular-season points, with the highest-ranked team facing the lowest. So Philadelphia, as the best of the second-place teams, gained the softest assignment, Smythe runner-up Vancouver, in those dangerous two-of-three preliminaries that get Cup play under way tonight.

Here is the outlook for the preliminary series, scheduled tonight, Thursday and, if necessary, Saturday. WDCA-TV-20 will televise a Saturday match, If any of the series last that long, at 2 p.m.

Vancouver at Philadelphia

The Canucks finished the season with 63 points, the same number as Washington, and under any realistic guidelines would not be playoff team. However, the rules allow the Smythe runner-up a free ride.

Next year there will be reform, with only the division winner an automatic qualifier. There also will be a 21-team league, so reform ends there - 16 clubs will qualify for playoff action and the opening round will be best-of-five.

In a seven-game series, Philadelphia would be a 100-to-1 favorite over the Canucks. Anything can happen in a best-of-three set, however, so the odds drop to about 8 to 1.

Rod Sedlbauer was a 40-goal scorer and Harold Snepsts had an exceptional year on defense, but otherwise the Canucks are badly outmanned. The Flyers have been hot, losing only three of their last 15 games, two of them to the Islanders. On the season, the Flyers had a 2-1-1 margin over Vancouver, with both victories coming on shutouts.

Radio: 610, if you live in the northern suburbs.

Los Angeles at New York Rangers

Playoff games usually call for close checking, but these teams don't know how to play that way. The Rangers took the season series, winning three of four, and outscored the Kings, 22-18.

Marcel Dionne placed second in the NHL point race with 59 goals and 130 points and he has scoring help from teammates Dave Taylor, 43 goals, and Butch Goring, 36. The Kings' defense is horrible, however, and does not figure to handle Phil Esposito, Anders Hedberg, Pat Hickey, Ron Duguay and company.

If Ulf Nilsson were healthy, the Rangers would be outside threats to go all the way.As it is, they will help reduce the playoffs to an east-of-the-Mississippi contest by Saturday.

Radio: 1010, if you don't mind frequent fadeouts.

Toronto at Atlanta

The Flames have the home-ice advantage as well as the third-highest scoring team in the NBL. They also possess a history of playoff futility, never having won a postseason series.

Coach Roger Neilson's job is reportedly forfeit in Toronto unless the Leafs reach the final. There is no way they will get that far, but the emotional angle should lift them past Atlanta into a quarterfinal rumble with Montreal.

Atlanta won four of five regular-seasons meetings, largely on excellent goaltending of Dan Bouchard. With Mike Palmateer in the Toronto nets, this should be a goalies' series, as well as a most physical matchup.

Radio: Flip the dial for a Canadian station.

Pittsburgh at Buffalo

Both teams played well down the stretch, then went for a stake on Sunday. They could find it difficult returning to hockey.

If you can get good odds on the possibility of an overtime game, take the plunge in this series. The teams tied all five meetings a year ago and deadlocked two more this season before the Penguins won the last two games.

This should be another high-scoring matchup, with the Sabres maintaining their late surge under Coach Billy Inglis. It's too bad the coach-of-the-year ballots are already in. Johnny Wilson has done an exceptional job in Pittsburgh, too, and they probably ought to determine the winner by the outcome of this series.

Radio: 1020, reasonably clear. CAPTION: Picture, Mike Bossy of Islanders exults after goal against John Davidson of Rangers. Bossy's two third-period goals gave him 69 for season, second highest total in NHL history. Phil Esposito ranks first with 76. UPI