Realistically, the Boston Celtics are perilously close to back-to-back losses. Without Paul Pierce’s heaved three-pointer against New York on Sunday and a late comeback against Houston yesterday, the Celtics would take a two-game losing streak into tonight’s meeting with Philadelphia.

But instead, five straight losses have turned into five straight wins, and the Celtics have an opportunity tonight to seize the Atlantic Division lead, an accomplishment that carries with it the Eastern Conference’s No. 4 seed. Perhaps more importantly, the Celtics are thriving as their Core Four surges.

Rumors spread around this team like wildfire right as the Celtics are finding their stride. Forget the five straight wins — as I mentioned before, the Celtics could easily have back-to-back losses, so wins aren’t always a perfect measure. Instead, note the performance of the Core Four, who are finally co-existing peacefully and with synergy. Kevin Garnett has double-doubles in seven of his last eight contests. Rajon Rondo is averaging 14 points, 13.75 assists and 8.25 rebounds in his last four. Paul Pierce has two straight 30-plus point performances. Ray Allen continues to emerge open (or sometimes not so open) on the perimeter at perfect times. It is the way things used to be, Boston’s four best players helping to make things easy for each other, carrying the load for teammates who won’t always perform, stealing wins even when the bench provides next to nothing.

The difference between victories and losses in the NBA is often an inch or two, and the Celtics are presently winning the tug-of-war for that inch.

They easily could have lost against Houston yesterday in an ugly affair. Paul Pierce threw a pass directly into Courtney Lee’s hands in the backcourt. Rajon Rondo missed a wide open layup by three or four miles. Kevin Garnett missed a crucial set of free throws. The Celtics shot just 43 percent and got outrebounded 57-38. Yet for some reason — let’s call it defense, with a dash of timely shooting — the Celtics erased a 10-point fourth quarter deficit to take down Houston and set the scene for tonight’s meeting with Philadelphia.

“I mean, it was a no-energy game. You can feel it. I even said at halftime, ‘Even the building had no energy,’ ” said Doc Rivers, as quoted in the Boston Herald. “It’s just one of those nights. And our guys kept talking about grinding the game, ‘We’ve got to grind this game out somehow.’

“And I thought there was a stretch, I don’t know when, we were down eight with three minutes, four minutes, you could hear them in the timeout. You know, I don’t know if we were going to win or lose, but you knew we were going to have a chance. You just felt that.”

The five consecutive wins glow with significance, not just because the Celtics are scaling the conference standings, which they are, but because they are showing glimpses of competitiveness right before the trade deadline. It’s unlikely that Boston can change Danny Ainge’s mind — he probably has his opinion set that the Celtics are not championship contenders, a theory that makes all kinds of sense when considering the skill (and youthful athleticism) in Miami and Chicago — but if it’s possible to make one of the league’s itchiest trigger fingers less itchy, the Celtics are putting forth their best effort.

The Celtics have won five straight games, yes, but more importantly they have Connect-ed Four. In possibly their final couple weeks of playing together, the Core Four has started to sing in beautiful harmony again. They won’t hit the high notes forever, but for now, the sound is soothing.