YOKOHAMA, Japan — When New Zealand and South Africa were drawn into the same pool for this year’s Rugby World Cup, even casual fans took notice.

Two of the sport’s super-heavyweights, they have met 45 times since 2000. Recently, they have seemed as evenly matched as ever: the last four meetings between the sides had all been decided by two points or less, with an aggregate score of 107-106.

With three lower-ranked teams — Canada, Italy and Namibia — in their first-round pool, New Zealand and South Africa both are expected to advance to the quarterfinals. That made their meeting on Saturday in their opening game not a must-win match, but something more like a measuring stick.

The result — a 23-13 New Zealand victory — showed clearly how much will be needed to knock the All Blacks, the two-time defending Rugby World Cup champions, off their throne.