Things started badly for the Reds at St. James' Park, with Virgil van Dijk shown a straight red shortly after the hosts had taken the lead through Anthony Gordon.
However, a Darwin Nuñez double in the second half sealed a memorable victory against the odds, leaving the travelling support in raptures.
Amid the euphoria, there were concerns that Liverpool may be facing a defensive crisis for the coming visit of Aston Villa.
Van Dijk will be suspended for the fixture on Sunday, 3 September, while Ibrahima Konate missed the Newcastle win with a muscle issue and could still be a doubt.
Matip, who was brought in this weekend to deputise for the Frenchman, was subbed in the second half at St. James' Park, with 20-year-old Jarell Quansah making his senior debut.
It led to some concerns that Matip too had picked up a knock – a scenario that could leave the Reds desperately short for the next game.
However, Klopp insisted post match that there is no such problem and that tiredness was the real reason for Matip's withdrawal.
The Liverpool manager said: "No, no. The big man looked a bit tired, let me say it like this. It is long ago the boys now played a full 90 minutes, these kind of things. Joey played obviously 70 and we have Quansah.
"It’s great. He’s a real talent. He played two really good passes, super-important passes, I would say. Defensively we needed luck a little bit, we were a bit too deep, a bit too passive, they could shoot but we have Ali. There were, obviously, besides the result a few nice stories and bringing Quansah on is one of them."
Liverpool have been tipped to move for another defender in the transfer market, with a younger, versatile option preferred. However, few names have been credibly linked and time is running out to complete a deal with Deadline Day approaching this Friday.