A much-changed Sweden side reached the Women's World Cup round of 16 with a perfect record after Rebecka Blomqvist's second-half header and substitute Elin Rubensson's 90th-minute penalty helped them beat Argentina 2-0 on Wednesday.

Blomqvist met Sofia Jakobsson's cross with a fantastic header in the 66th minute to put the third-ranked Swedes firmly on course to advance as Group G winners, with Rubensson sealing the win with a superbly taken spot kick.

Argentina, who lost midfielder Florencia Bonsegundo to injury minutes before the break, needed a victory to stand any chance of going through but never really troubled the Sweden defence or goalkeeper Jennifer Falk.

They remain without a win in their four World Cup appearances and finished bottom of the group.

Sweden will next face holders United States in a blockbuster clash in Melbourne on Sunday -- a rematch of the Olympic quarterfinals in 2021 when the Europeans won 3-0 en route to the final.

Having already secured qualification after winning their first two games, Sweden only needed a point to top the group and coach Peter Gerhardsson made nine changes to the side that thrashed Italy 5-0.

Only defenders Amanda Ilestedt and Magdalena Eriksson retained their places and Sweden were far from their rampant best, with Olivia Schough's weak free kick their only shot on target in a disjointed first half.

Blomqvist finally got the breakthrough after the hour mark and was brought down inside the penalty area by Gabriela Chavez in the closing minutes to allow Rubensson to drive the resulting penalty into the roof of the net.