Even with a spate of injuries and seven starting lineups in 14 games, the Celtics have managed to win 12 straight games since that shaky start they had in the first week . Coach Brad Stevens has been heaped with credit for the run, but specifically, we should credit Stevens defense. The Celtics were Deebo Samuel Jersey a good defensive team last year, ranked 12thin the NBA in efficiency as they allowed 105.5 points per 100 po se sions.This year, though, no team has made a bigger defensive leap, dropping all the way to 95.4 points per 100 po se sions. That improvement has the Celtics, even with the injuries theyve had, looking like a legitimate contender in the Eastern Conference, seeking to become the first non-LeBron James team to reach the NBA Finals since Doc Rivers Celtics did it in 2010.It also has them atop this weeks Power Rankings, with a focus on defense. (All statistics come from NBA.com stats.)MOCK DRAFT: 1. Celtics:Marcus Smart has been a constant for Boston over its 12-game winning streak. With a 94.7 defensive rating and a plus-11.6 net rating, Smarts defense has made it easy to overlook his shooting struggles.2. Warriors:Kevin Durant is averaging 2.4 blocks, well above last years career-high of 1.6. The Warriors lead the league with 9.0 per game, which would be a new NBA record (8.7 is the current mark, by the 1985-86 Bullets).3. Rockets:Hard to believe, but Rockets opponents are outscoring Houston in the fast break, 21.6 points to 20.7 per game. Theyre last in efficiency defending the break (1.22 points per po se sion) so far this season.4. Pistons:The Pistons, winners of eight of their last nine, were 27thwhen it came to forcing turnovers last year (12.8 per game). This year, theyre Top 5 (16.5 per game). 5. Spurs:Mi sing Kawhi Leonards pick-and-rolldefense. Last year, they were seventh defending the play. This year, they are 26th. Still have managed to stay seventh in defensive efficiency.6. Nuggets:Denvers defensive efficiency has gone from 110.5 last year to 104.4 this year, which ranks sixth in year-over-year improvement in that stat.7. Wizards:Theyve been middle-of-the-pack defensively this year (15thin efficiency Jerick McKinnon Jersey ), but have allowed 0.72 points per po se sion in the pick-and-roll, third in the league.8. Raptors:The ability to stop penetration has been a problem, as Toronto has allowed 29.0 shots per game from the restricted area. Thats up from 26.0 last season, when they were eighth.9. Grizzlies:So far, theyve allowed only one opponent to top 50 percent shooting in 12 games (8.3 percent of their games). Last year, they allowed 50 percent or better 18 times (22 percent). 10. Trail Blazers:Portlands rebounding percentage has gone from 49.8 last year (18th) to 54.2 percent this year (first). Thats cut opponents attempted field goals from 86.2 to 83.0, and Portland has been the Tevin Coleman Jersey third-most improved defensive team this season (from 107.8 points per 100 po se sions to 100.5).11. Timberwolves:Minnesota is terrible at defending the fast break. Last season, they were 29th, allowing 1.17 points per po se sion. This year, 26th and 1.16 points per po se sion.12. Magic:Typical of a young team, the Magics defensive efficiency at home has been great, 100.1 points per 100 po se sions, seventh in the league. But on the road, its 105.7, which ranks 16th.13. Pelicans:Theyve won four of their last five, and in that stretch, their defensive efficiency (99.5) has ranked third in the league.14. Thunder:Good signs on the defensive end, where they are No. 2 in efficiency,lead the league in deflections (18.6) and are second in loose balls recovered (7.7). Offense will come, but the defensive effort is there. 15. Sixers:Philadelphiahasbeen lucky on 3-point defense. They allow the second-most wide-open 3s in the league (18.2 per game), but opponents have shot a mediocre 37.2 percent on those shots.16. Knicks:Perimeter defense is a problem, but their defense in the paint has been surprisingly good. New York is allowing just 56.4 percent shooting on shots taken in the restricted area, which ranks second in the league.17. Bucks:What happened to the perimeter defense? They were top 10, allowing 35.3 percent on 3s last year. Now theyre 28th, allowing 38.7 percent.18. Heat: Six-game road junket went well defensively, especially before Sundays lo s to Detroit. Wrapped up with a defensive efficiency rating of 99.9 on the trip.19. Jazz:They are ranked third in defensive efficiency, fifth in shooting percentage allowed from inside five feet and sixth in fewest shots allowed within five feet. But theyll have to keep that up . 20. Cavaliers:Last year, the Ds problem was that it could not stop the pick-and-roll, Roger Craig Jersey and adjustments were made. This years problem is bigger: The Cavs cant stop much of anything. Not sure how to adjust on that.21. Pacers:The Pacers were No. 4 in the league when it came to allowing points in the paint last year (39.7 per game). This year, they are 28th(50.3 per game).22. Clippers:First five games: 92.4 points allowed per game, 40.4 percent shooting, 31.5 percent on 3s. Last seven: 115.0 points, 49.7 percent on FGs and 42.1 percent on 3s.23. Hornets:Charlotte added Dwight Howard to a team that was already good at defending the paint, at 40.5 points allowed per game last year. This year, that is up to 41.2 points allowed in the paint per game.24. Lakers:Could be a sample-size thing, but the Lakers guarding the 3-pointer this year: 31.6 percent, which is third in the NBA. Last year: 37.0, and 26thin the league. 25. Nets:Showed some defensive promise in the last four games of their road trip. Allowed 103.8 points, 43.2 percent shooting and 30.6 percent 3-point shooting, and split the four games.26. Suns: The hustle stats dont look good for Phoenix: 0.36 charges drawn, 28thin the league, and 10.4 deflections per game, 29th.27. Kings:Dave Joerger was once considered a defensive coach. Now, his team ranks seventh in giving up wide-open shots (27.5 percent) and last in field-goal percentage on those shots (47.9 percent).28. Hawks:Atlantas defensive efficiency was 103.1 last season, and its Joe Staley Jersey ballooned to 107.8 points per 100 po se sions this year. No team has gotten worse defensively in relation to last season.29. Mavericks:The Mavs have been worst in the league at defending ball handler pick-and-rolls (0.97 points per po se sio