By Marc Stein ESPN.com Thanks to a stubborn foursome of 50-win teams, there is typically only one spot up for grabs every Monday in the top five of ESPN.com's weekly NBA Power Rankings. And the Houston Rockets have grabbed it. For the first time since way back in Week 4, Houston has risen to No. 5, having displaced San Antonio thanks largely to Sunday's road slaying of the Spurs. The win was so Texas-sized that the Rockets -- now 16-4 since losing Tracy McGrady for the rest of the season -- have seized sole possession of first place in the Southwest Division, which marks the latest point in a season in which they've been alone in first place since they won the old Midwest Division, and eventually their first championship, in 1993-94. http://sports.espn.go.com/nba/powerranking?season=2009&week=21&campaign=rss&source=NBAHeadlines
