Eddie Howe's side are only off the bottom ofthe Premier League on goal difference and have lost their opening four games in a season for only the third time.
The Norwegian has had to wait to find the net since his return from the foot injury that sidelined him for most of December and January, but he made up for lost time here.
Xabi Alonso's side have not lost any of their 24 competitive games this season, a joint record for any German side from the start of a season - after Hamburg, who went on to win the title and European Cup in the 1982-83 campaign.