The All Blacks are showing off their prowess on the field, but for many subscribed to Spark Sport, they can't see it.
Many are complaining on Twitter about buffering and the stream cutting out.
Responding to the criticism, Spark Sport is making the rest of the match "available immediately" on a TVNZ channel.
"A small percentage of our customers are experiencing streaming issues when watching the All Blacks v South Africa match.
"We apologise to those impacted."
Spark chief executive Jolie Hodson also tweeted: "Disappointing after a night of good coverage but it's the right thing to do for those impacted customers".
Twitter is inundated with tweets complaining about the coverage.
"Are you going to refund me then?" said one user. "We had about 20 interruptions in the first half after the Aussie and then Argie games were perfect. Horrible experience. Appreciate going to the fall back option. Please get this sorted for following games!!" said another.
"Streaming generally well here, with a few resolution drops. Doubtless helps that we're on a Spark connection. Much more of a sense of pressure on the network than last night," says journalist Russell Brown.
Some users, however, said that they hadn't had issues.
"Been perfect for me all day," said one. "It’s all going great for me," said another.
In a statement, Spark Sport said more details about the decision to move to television would be provided soon.
The Japan v Russia match on Friday night was viewed by almost 60,000 subscribers, and Spark Sport says less than 1 percent experienced technical issues. But it stressed it was keeping its phone and online helpdesks open on Saturday night.
On Friday, Spark was under fire after some customers received letters saying their broadband wasn't up to scratch, and they'd have to find alternative ways to watch the opening match.
Between June 17 and September 12, Spark offered a free World Cup Tournament Pass to new broadband customers, or existing customers who renewed a contract or upgraded their plan.
Spark said the late surge of subscribers to the World Cup pass had caused issues with "cross-checking" the quality of those connections.
Spark has previously acknowledged that not all homes could run the World Cup pass, due to the quality of their broadband connection.