The Boston Celtics improved their playoff record to 5-0 with a resounding 112-20 win over the top-seeded Milwaukee Bucks on Sunday afternoon, which is all the more impressive considering that they are without probably their best defender.

Marcus Smart suffered an oblique injury in the final week of the regular season, and almost immediately was thought to be out for at least 4-to-6 weeks. However, Smart seemed to be making good progress during the team's first-round series win over the Indiana Pacers, and a few days ago he began running sprints and shooting jumpers.

Despite the optimism that Smart could return ahead of schedule, however, Celtics head coach Brad Stevens thinks that the original 4-to-6 week timeline is still the most likely for Smart's full recovery:

Even without Smart, the Celtics have been arguably the best defensive team in the playoffs thus far. Through the first five games, Boston's defensive rating of 94.6 is the best of any postseason team, according to NBA.com.

In their win over the Bucks on Sunday afternoon, the Celtics held Milwaukee to under 35 percent shooting from the field and just 26 points in the paint while also tallying 11 blocks. Their team defense was on full display as they harassed Bucks superstar Giannis Antetokounmpo into 7 of 21 shooting and numerous blocked shots.

Smart has been a vital piece of Boston's identity all season long, and Stevens would love to have him back in the rotation. But with the Celtics taking the series opener and stealing the home court advantage, they will not rush Smart back into action before he is ready or absolutely needed.