Jordan Angeli got her side off to the perfect start, netting the first goal of the WPS season after just 18 minutes before Keelin Winters made it two just five minutes later.
Kelley O'Hara, who came into the fray as a replacement for the injured Angeli after half an hour, grabbed a goal on her debut with just 20 minutes remaining and put the Breakers out of sight.
Beat dominated the statistics at the final whistle and Boston had goalkeeper Alyssa Naeher to thanks for keeping them in the game after a string of impressive second half saves.
The hosts did get on the scoresheet from the penalty spot thanks to Carli Lloyd but the visitors ended the rout with a spot kick from Kasey Moore.
The second game of the season sees Philadelphia Independence travel to New Jersey to take on Sky Blue FC on Sunday. The game kicks off at 6pm local time (2300 GMT).
