Every year, the Subway Series serves as a sort of litmus test for the Mets’ latest zany scheme to make themselves over into an elite team. Traditionally, these efforts have only come to grief.

This year, perhaps more so than any other year since interleague play began in 1997, the Mets’ achievements seem to be in line with their ambitions: This is not only a very good ballclub, but an exceptionally well-balanced one. The Amazins boast speed, power, patience, defense, starting pitching, and a first-rate bullpen. The Yankees, as usual, are heavier on the power and patience than anything else, but it doesn’t much matter – even with Gary Sheffield and Hideki Matsui on the disabled list, they’re quite capable of bludgeoning the Mets. Whether they can do so will probably be the key to the series.

Tonight’s matchup between Randy Johnson, arguably the greatest left-handed pitcher in baseball history, and Jeremi Gonzalez, a junk-balling righty whose earned run averages were 6.11 and 6.97 in his last two stints in the majors, isn’t as big a mismatch as it seems.

Johnson has struggled terribly lately – his ERA this month is 6.06 – and has neither his traditional velocity nor command. Among the Mets’ key hitters, only Carlos Delgado is a lefty, and he’s not the kind of all-or-nothing slugger who can’t do a thing with even a struggling Johnson.

Gonzalez, meanwhile, is just cannon fodder, but all he really needs to do is keep the game within reach for four or five innings and let an incredibly deep bullpen take over from there. The Yankees obviously have the advantage here, but if Johnson does what he’s been doing lately and gives up a run for every inning he pitches, it’s going to be a game.

One thing to keep an eye on: Johnson has been striking out many fewer batters than usual lately, and walking many more, while the Mets’ lineup is very disciplined and can string together a long sequence of hits and singles. If Johnson puts on a poor show, it’s quite likely that it will be a death by a thousand cuts, rather than annihilation.

Saturday’s game will be the marquee matchup. Mike Mussina is pitching like he’s 25 again, while Pedro Martinez remains one of the most impressive hurlers in baseball. This one will live up to the hype, and should be an absolute pitching clinic, as both starters rely more on reading hitters, mixing their pitches, and changing speeds than on velocity.

The undefeated Martinez probably gives the Mets the edge here, but Mussina’s much more of a big-game pitcher than he has a reputation for, and these two have locked horns in plenty of classics through the years, dating back to the days when Martinez was in the middle of the most dominant stretch of pitching in baseball history.

Saturday’s game will likely be decided by a mistake pitch or two, and you have to think that Martinez isn’t going to make any mistakes pitching in front of the Shea faithful.

Sunday’s game is probably a bigger mismatch than tonight’s. The Yankees announced yesterday that Aaron Small, who’s pitched all of 10.1 innings this season, will be filling in for Shawn Chacon, who has a large welt called a resolving hematoma just below the knee on the inside of his left leg, which he got when he was hit by a batted ball last Thursday against Boston.

Chacon is only expected to miss one turn in the rotation, but that’s less of a consolation after his last outing, when he served up eight runs to the Rangers in little more than an inning.

Glavine, meanwhile, has been the best pitcher in baseball since last summer’s All Star break and has thrown at least six innings while giving up three or fewer runs in all but one game this year. His new willingness to establish his fastball inside has given his usual assortment of change-ups away more credibility, and he’s as tenacious and efficient as he’s ever been in his career.

Pitching matchups aside, most advantages go to the Mets right now. The Yankees’ lineup core of Alex Rodriguez, Derek Jeter, and Jason Giambi is the most devastating in the game, but due to injuries the Mets have a longer offensive sequence, while their core of Delgado, Carlos Beltran, and David Wright is certainly nothing to scoff at.

The Yankees have a poor defensive club, deficient in range and full of the stone-handed likes of Giambi and Melky Cabrera, while the Mets have a pretty fair one, though not as good as their reputation would suggest.

The Mets have a big advantage in the pen, as Duaner Sanchez, Aaron Heilman, and the terrifying (to foes and Mets fans alike) Jorge Julio are all better than any Yankee set-up man, and Sanchez and Heilman are more than capable of going two innings at a time. Mariano Rivera is better than Billy Wagner, but not enough to offset that.

All these paper advantages aren’t going to mean much for the Mets if they don’t execute, though, which is where the Yankees have a pretty big advantage. Whether it’s Wright botching three balls in a game, Beltran toeing the line between discipline and passivity at the plate in big spots, or Heilman throwing away the ball to end games, the Mets’ weakness this season has been their propensity for questionable fundamental play at key moments in games.

The Yanks have had some problems there, too, but no one worries that Derek Jeter is going to refuse to swing at a hittable pitch a couple of inches off the plate in a key RBI spot, or that Mariano Rivera (the 2001 World Series aside) is going to throw a game-ending groundout away in the bottom of the ninth. Doing what needs to be done in the moment of pressure is one thing that’s separated the Yankees from an awful lot of other teams over the years, and no matter their advantages, if the Mets can’t do the same those advantages aren’t going to do them much good at all.

tmarchman@nysun.com