LOS ANGELES — Wrapping up an NL West title has become routine for the Los Angeles Dodgers, but in a year in which no one was sure three months ago if there would be a baseball season, manager Dave Roberts wanted his team to savor the moment. The Dodgers clinched the NL’s top postseason seed and eighth straight division title with a 7-2 victory over the Oakland Athletics on Tuesday. They are the third team to win at least eight straight division titles, joining the Atlanta Braves (14 straight from 1991 to 2005) and New York Yankees (nine straight from 1998 to 2006). “To fast-forward a couple months and be crowned NL West champs is a credit to everyone. It should never be taken for granted,” Roberts said. “Truth be told, a lot of guys didn’t know we could clinch. We were responsible, but I let it know that it has to be appreciated.” The Dodgers, who own the best record in the majors at 39-16, were the first team in baseball to clinch.