Australia set an Olympic record to win gold in the 4x100m women's relay.
"What a shock to see Australia take that title. We expected to them be strong in the 4x200m freestyle but not so strong in the shorter relay. For Great Britain, it was an impressive swim by Fran Halsall. It will lift her for her individual races."
The Netherlands, who won gold in Beijing and are the reigning world champions, claimed silver, with the United States taking the bronze.
Great Britain's quartet of Amy Smith, Fran Halsall, Jessica Lloyd and Caitlin McClatchey were third at the halfway point but eventually finished fifth.
Halsall gave GB hope of a bronze with her swim on the second leg, with just Australia and the US in front of them.
But the Dutch made a late surge to grab second, with China also overtaking the Brits.
"At the World Championships last year, we didn't make the final," said Halsall. "We were ninth, so it shows how much we have improved."
Final results by Country
View full results for Women's 4 x 100m Freestyle Relay
Coutts, Campbell, Elmslie, Schlanger, Seebohm, Kukla, Trickett
Australian Olympic Team
Dekker, Veldhuis, Heemskerk, Kromowidjojo, Schreuder
Franklin, Hardy, Neal, Schmitt, Weir, Coughlin