Springboks coach Rassie Erasmus arrived later than he normally does for his team's pre-game warmup in Toyota. Turns out he couldn't take his eyes off another Rugby World Cup game.

Somewhere in the backrooms at the City of Toyota Stadium, Erasmus was instead glued to the TV for the Japan-Ireland epic in Shizuoka, which ended less than an hour before his team's game against Namibia.

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South Africa's coach Rassie Erasmus takes a drink as his players warm up ahead of the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's coach Rassie Erasmus takes a drink as his players warm up ahead of the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's coach Rassie Erasmus gestures as his players warm up ahead of the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's coach Rassie Erasmus gestures as his players warm up ahead of the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

Japan's players wave to supporters after winning over Ireland during the Rugby World Cup Pool A game at Shizuoka Stadium Ecopa between Japan and Ireland in Shizuoka, Japan, Saturday, Sept. 28, 2019. (Kyodo News via AP)

Japan's players wave to supporters after winning over Ireland during the Rugby World Cup Pool A game at Shizuoka Stadium Ecopa between Japan and Ireland in Shizuoka, Japan, Saturday, Sept. 28, 2019. (Kyodo News via AP)

South Africa's Schalk Brits scores a try as he is tackled by Namibia's Eugene Jantjies during the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's Schalk Brits scores a try as he is tackled by Namibia's Eugene Jantjies during the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's Siya Kolisi scores a try during the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's Siya Kolisi scores a try during the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

"I watched that game right to the end," Erasmus said.

South Africa's coach Rassie Erasmus takes a drink as his players warm up ahead of the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's coach Rassie Erasmus takes a drink as his players warm up ahead of the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

And apart from the great drama of Japan's 19-12 upset victory over Ireland, which shook up the World Cup, it might also have been time well invested by Erasmus.

Should Japan keep its stunning run going in Pool A, and South Africa clinches second in Pool B, it'll be Japan vs. the Springboks in the quarterfinals.

And that'll put South Africa in Japan's sights once again. The Boks have been there before, beaten in the last seconds by Japan at Rugby World Cup 2015 for the biggest shock in the tournament's history before Saturday in Shizuoka.

South Africa's coach Rassie Erasmus gestures as his players warm up ahead of the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's coach Rassie Erasmus gestures as his players warm up ahead of the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

Erasmus said a quarterfinal against the host nation is now "a realistic option" if South Africa can get past Italy, the biggest challenge it has left in the pool stage.

"It's also a bit of a scary option," Erasmus said.

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Japan's players wave to supporters after winning over Ireland during the Rugby World Cup Pool A game at Shizuoka Stadium Ecopa between Japan and Ireland in Shizuoka, Japan, Saturday, Sept. 28, 2019. (Kyodo News via AP)

Japan's players wave to supporters after winning over Ireland during the Rugby World Cup Pool A game at Shizuoka Stadium Ecopa between Japan and Ireland in Shizuoka, Japan, Saturday, Sept. 28, 2019. (Kyodo News via AP)

South Africa's Schalk Brits scores a try as he is tackled by Namibia's Eugene Jantjies during the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's Schalk Brits scores a try as he is tackled by Namibia's Eugene Jantjies during the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's Siya Kolisi scores a try during the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)

South Africa's Siya Kolisi scores a try during the Rugby World Cup Pool B game at the City of Toyota Stadium between South Africa and Namibia in Toyota City, Japan, Saturday, Sept. 28, 2019. (AP PhotoChristophe Ena)