Portugal dominated Luxembourg in the first and third quarters en route to a 77-61 triumph in the Group B opener for both sides.
Susan Foreid had 16 points and nine rebounds for the Portuguese, who stormed out to a 21-7 lead but allowed the tiny central European nation to close to within 37-31 by half-time.
The hosts re-established a 59-43 lead by the end of the third quarter and cruised to victory.
Portugal made a commitment to getting the ball inside and were 26 of 50 (52%) from two-point range.
When they weren't scoring down low, they were being fouled and earning trips to the line where they made 22 of 29 (75.9%). Outside the arc, they were just one of 15 (6.7%).