FOR THEIR EFFORTS, THEY'LL FACE AN ACE; FRANCHISE-BEST SEASONS NET ASTROS, PADRES SHOWDOWN.

Byline: Daily News Wire Services

Overwhelming versus nasty.

It won't be a pleasant day for hitters when Houston's Randy Johnson and San Diego's Kevin Brown, two of baseball's most dominating pitchers, provide a marquee matchup in the opener of the NL division series between the Padres and Astros today.

Johnson, of course, is the Big Unit, a 6-foot-10 left-hander who virtually no one relishes facing. Brown's pitches have so much movement that they've been described as ``nasty.''

And this is what the Astros and Padres get for posting their best seasons ever?

``It ain't' fun,'' San Diego batting star Tony Gwynn said of facing Johnson. ``Probably the biggest challenge you have as a left-handed hitter in this league is facing Randy Johnson. When he's on, you can't hit him.''

After his trade from Seattle on July 31, Johnson went 10-1 with a 1.28 ERA, led the majors with 329 strikeouts and has been unbeatable in the Astrodome, going 5-0 with four shutouts.

``When he pitches, he wins, and he gives us confidence,'' manager Larry Dierker said.

Johnson has faced left-handers just 18 times since joining the Astros, allowing four hits.

Padres manager Bruce Bochy said Steve Finley, the left-handed center fielder, will play, but he was unsure about first baseman Wally Joyner, a left-hander who has been bothered by a sore left shoulder. If Joyner can't go, he'll be replaced at first base by right-hander Jim Leyritz.

Brown was a big catalyst in the Padres' 98-win season. He went 18-7 with a 2.38 ERA and 257 strikeouts. He won 14 of 15 decisions from May 26-Aug. 25, including 11 straight.

``I knew Kevin Brown would make a difference on this ballclub. I just didn't know it would be this much,'' Padres manager Bruce Bochy said.

Both teams were swept the last time they were in the playoffs, Houston by Atlanta last year and San Diego by St. Louis in 1996. Houston has never won a postseason series.

Matchups

San Diego: The Padres were shaped on Dec. 28, 1994 in the 12-player trade for third baseman Ken Caminiti and Finley with the Houston Astros. The Astros still have outfielder Derek Bell and shortstop Ricky Gutierrez from that deal. . . Vaughn hit two home runs in a win at the Astrodome on May 22. He has six homers this year vs. the Astros. . . In their only game against Johnson this year, the Padres struck out 12 times in losing 2-1 on June 24 when Johnson was still with the Seattle Mariners.

Houston: The Astros ended Padres closer Trevor Hoffman's then-record streak of 41 straight saves when Moises Alou hit a home run in the ninth inning on July 26 at San Diego. Houston won in 10 innings. . . Closer Billy Wagner had three saves with 0.00 ERA against Padres.

Big picture:

San Diego: The Padres ran away with their second NL West title in three seasons under Bochy, opening a double-digit lead on July 18 and setting a team high with 98 wins. . . The team slumped in September, winning just eight of 21 games at one stretch and costing themselves a shot at home-field advantage. . . Vaughn had a resurgent season after struggling badly in 1997. He hit a club-record 50 homers. . . Hoffman tied Randy Myers' 1993 NL record for saves. . . Gwynn, Caminiti and Joyner are aging and fragile, and were affected by a variety of nagging injuries.

Houston: The Astros won their second straight division title, this time with a big boost from Johnson. . . They surpassed the 100-victory mark for the first time in franchise history, finishing with 102 wins. . . Alou came over from the World Series champion Florida Marlins and posted career bests in hits, runs, home runs, and RBI. . . Wagner survived a scary incident when he was struck on the side of the head by a batted ball on July 16 at Arizona. . . The Astros led the NL in runs scored, RBI and on-base average.

CAPTION(S):

2 Photos

PHOTO (1) The acquisition of Randy Johnson has made the Astros the trendy World Series favorite from the National League.

(2) No lead is safe? Think again. San Diego closer Trevor Hoffman converted 53 of 54 save opportunities during the regular season.

Kent C. Horner/Associated Press