Rico Petrocelli drove in three runs, Carl Yastrzemski smashed two home runs, and the Impossible Dream, Volume II, rolled through Detroit yesterday as the Red Sox downed the Tigers 7-3 in the season opener.

After Reggie Smith singled and rookie Joe Lahoud walked, Petrocelli smashed a double off loser Earl Wilson to drive in Boston's first two runs.

Yastrzemski, last year's triple crown winner, belted a solo round-tripper in the seventh and padded Boston's lead with a 420-fool inside-the-park homer in the ninth.

Veteran lefty Dick Ellsworth, making his American League debut after coming from Philadelphia in a winter trade, yielded nine hits in going the distance for the Golden Hose. He yielded a lead-off home run to losing pitcher Wilson in the third, but was in control for the rest of the game.

In other opening-day action the New York Mets blew a two-run lead in the ninth inning and lost to the San Francisco Giants 5-4. Also:

Cleveland 9 Chicago 0

Minnesota 2 Washington 0

Yankees 1 California 0

Cincinnati 9 Cubs 4

St. Louis 2 Atlanta 1

Houston 5 Pittsburgh 4