Last year this team was far worse than they looked on paper, mostly because they were able to completely wipe up against the worst teams in the league, thereby padding their record. As with many seasons, they had a problem getting completely destroyed by the better teams, barley scraping out any wins against the likes of the Yankees, Dodgers, etc.. (though they did get one or two).
We'll see if they can manage to go 500 against the elite teams this year. If the Tigers have entered that category, they'll get more chances than before to show they aren't a mirage.
While there are more than 100 games to go, we'll see how the teams that contributed to their win streak ultimately fare but it is heartening to think that they can also annihilate teams that are a step up above the worst in the league.