Heading into tonight’s Game 5 of the Eastern Conference finals, two things have become clear:

1) The Detroit Pistons are probably the better team; and

2) They probably aren’t going to win.

Those two conclusions were laid bare in Detroit’s 94-75 win over Boston on Monday, in which the Pistons scored the first 11 points and took the fight to the Celtics throughout. It evened the series at two games apiece, and that 2-2 tie is an accurate reflection of how even the play has been: Through four games, the composite score is a mere two-point edge for Detroit at 356-354.

However, the Pistons reached this point despite a fairly immense handicap: Their best player has been hobbled by injury. Point guard Chauncey Billups was the team’s second-leading scorer this season, but he’s unquestionably the straw that stirs their offensive drink. Not only did he average 17.0 points and 6.8 assists a game; he did it while playing only 32.4 minutes a game — a restriction placed on him because Detroit won so many blowouts and had so little to play for in the final two months of the season.

Nobody thinks of him as a superstar, but make no mistake: This guy is one of the best players in the league. Prorate his numbers to the normal 40 minutes that an All-Star normally gets, however, and you’ll quickly see how effective he was — it comes out to 21.0 points and 8.8 assists.

He did it with incredible efficiency too. Billups’s shooting percentage was an unremarkable 44.8%, but because he spiked it with so many foul shots and 3-pointers, he had a 61.9 True Shooting Percentage, the best of his career and the second-best among NBA point guards (Steve Nash was first).

The other side of the equation was that he made remarkably few turnovers. Billups had miscues on only 9.1% of the possessions he used; among starting point guards only Chris Paul, Baron Davis, and Derek Fisher were better.

So, without belaboring the point too much, we can safely conclude that Billups was among the league’s best players this season on a per-minute basis. My Player Efficiency Rating (a per-minute rating of a player’s statistical effectiveness) concurs, ranking him second only to Paul among NBA point guards and 10th overall — ahead of several players with bigger reputations and larger endorsement deals.

His play was a big reason the Pistons won 59 games this year, second only to Boston’s 66 … but unfortunately the conference finals have been a different story.

Billups pulled a hamstring in Game 3 of the Pistons’ series against Orlando in the second round; despite that setback Detroit won the final two games to claim the series. However, he’s looked anything but recovered in the first four games of this series.

Billups was invisible in a Game 1 defeat, finishing with nine points and two assists and sitting for a large chunk of the second half. In Game 2 he played better — in fact he was sparkling, with 19 points, seven assists, and no turnovers. Unfortunately, he also appeared to reinjure the hamstring in the second half.

That set up another failure in Game 3, another Detroit loss. Billups played just 27 minutes, and his numbers — six points, four assists, two turnovers — didn’t suggest he merited a longer look. It wasn’t just an off night against a tough defense either. He looked as bad as he played, appearing to favor the leg at times.

In Game 4, he repeated the earlier pattern from Game 2, rebounding with 10 points, seven assists, and no turnovers. Included was a dagger 3-pointer late in the fourth quarter that effectively put the game away. Though he shot only 3-for-12, he was a factor at both ends — he harassed Ray Allen into a 2-for-8 shooting night and came up with two steals.

Alas, Billups also repeated another pattern in Game 4 — reinjuring the hamstring. He tweaked it in the second half, and the effects were obvious. The close-up camera on Billups on his game-clinching 3 showed him hobbling into position, visibly favoring the leg, before catching a pass and going up for the icing shot.

It’s a testament to the quality of the Pistons that they’ve been able to keep this series even despite having Billups in such a limited state (not to mention a testament to Billups that he’s out there at all). Few other teams could survive an injury to their best player so seamlessly, but between the solid play of rookie Rodney Stuckey and the numerous other offensive options the Pistons possess, they’ve been able to weather the storm and keep things competitive.

Alas, they still must win two of the next three games with their point guard so diminished. And if anything, it appears Billups will be more, not less, affected by the injury in coming nights. The every-other-night format of the conference finals certainly does him no favors, giving him little opportunity for rest between games, and he appears in worse shape now than he did at the start of Game 1.

Moreover, the Pistons face a second big obstacle because they don’t have home-court advantage. In a best-of-seven series, history says the team without home court has slightly worse odds when the series is tied 2-2 than they do when its tied 0-0. In other words, the Pistons have accomplished nothing yet.

They still have to win one of the two games in Boston’s TD Banknorth Garden — that’s no easy feat, although it’s one the Pistons pulled off Game 2. And they have to successfully defend home court in Game 6, or the other accomplishment is rendered moot. That would be a large task even with a healthy Billups; it seems monumental given his limitations.

It’s a shame because there’s little doubt Detroit has been the better team this postseason. Although Detroit played better teams in each of the first two rounds, it is 10-5 in the playoffs; Boston is 10-8. Detroit is 4-3 on the road in the playoffs; the Celtics are 1-7. And of course, the Pistons lead the series in composite score despite having their best player hobbled.

Coaches are fond of saying that the best team always wins in a best-of-seven series, but this year’s Eastern Conference finals may be a rare exception. Between the hamstring injury to Billups and the lack of home-court advantage, there’s a good chance Detroit is headed for its fourth conference finals exit in six years. Unlike the past three, this one would be very much undeserved.

jhollinger@nysun.com