Japan made the ideal start in their bid to add Olympic gold to their world crown by defeating Canada 2-1 at the City of Coventry Stadium on Wednesday evening.
Japan took the lead in the 33rd minute with a goal from Nahomi Kawasumi following a clever back-heel by Shinobu Ohno to set up the opening.
Japan scored again in the 44th minute when Canada's goalkeeper Erin McLeod failed to collect a cross from the left and Japan captain Aya Miyama headed into an empty net to give the Japanese a 2-0 lead. Canada responded at the start of the second half with a goal in the 55th minute from Melissa Tancredi, but Japan held on for victory.
Also in Group F, Sweden, who lie fourth in the world, began their campaign with a 4-1 victory against South Africa at the same venue in Coventry.
Sweden went ahead in the seventh minute through a deflected shot from captain Nilla Fischer, and hit the woodwork three times before Maria Dahlkvist made it 2-0 in the 20th minute, with Lotta Schelin getting a third a minute later.
Portia Modise pulled a goal back for South Africa with a spectacular strike from the centre circle, but Schelin made it 4-1 three minutes later to complete the scoring.
In Group G, the USA beat France 4-2 while Colombia surprisingly lost 1-0 to DPR Korea. Alex Morgan scored twice as the USA came back from two goals behind at Hampden Park. Gaetane Thiney and Marie-Laure Delie had given France an early lead, but Abby Wambach and Morgan made it 2-2 after 32 minutes.
Carli Lloyd put the USA in front on 56 minutes before Morgan secured the victory from close range ten minutes later.
Later in Glasgow, two goals from Kim Song Hui gave DPR Korea an unlikely win over Colombia in a match that was delayed by an hour because of a mistake at the stadium over a flag. The South Korean flag was wrongly shown in the opening video presentation and had to be changed, When the game got underway, striker Kim Song Hui opened the scoring in the 39th minute and then added a second five minutes from the end to give the Koreans a famous victory.