SAN ANTONIO — The San Antonio Spurs can open the season 5-0 for the first time in franchise history.That this storied franchise has never won its first five games is only slightly more surprising than the team that now has a chance to do so.San Antonio hosts Miami on Thursday after winning its first four games by an average of 16.5 points.In their 53-year history in San Antonio, the Spurs have won five NBA championships, matched a league record with 22 straight postseason appearances, and 21 winning streaks of 10-plus games.Their best start to a season is 4-0, though, which happened four times.“The Spurs never went 5-0? I’m surprised,” Spurs star Victor Wembanyama said. “I’m really surprised because the Spurs have the highest winning percentage in the last 30 years or whatever. Wow. Let’s beat that record.”The Spurs, Heat and Sacramento Kings are the only NBA franchises without five straight wins to open a season.Wembanyama is a huge reason for San Antonio’s undefeated start. The 7-foot-4 star from France was the season’s inaugural Western Conference Player of the Week and became the first player in league history with at least 100 points and 15 blocked shots in a team’s first three games.“He’s been amazing,” said Raptors forward Sandro Mamukelashvili, Wemba …