Japan coach Jamie Joseph acknowledged the pressure of hosting the Rugby World Cup led to a nervous performance from his side against Russia.
Tournament hosts Japan won 30-10 in the opening match on Friday, though trailed for much of the first half following Kirill Golosnitskiy's early try.
Kotaro Matsushima stole the show with a hat-trick, however, edging Japan in front prior to the interval having previously reduced the deficit, before rounding off the victory in the second half.
But Brave Blossoms coach Joseph conceded Japan found it hard to cope with the pressure in Tokyo.
"The game showed that the boys were nervous, as we spoke about before the game, there's so much expectation on the guys," said Joseph, who replaced current England coach Eddie Jones as Japan's boss.
"I thought we prepared well for it but it's not until you get out there amongst it and then you realise just how much pressure there is on the guys.
"I'm proud of the way they came through it in the end. We made a lot of unforced errors, our kicking game was pretty poor tonight so we’ll have to fix that up quickly.
After becoming the first ever Japanese player to score a hat-trick at a Rugby World Cup, the first @mastercard Player of the Match for #RWC2019 is Kotaro Matsushima #StartSomethingPriceless #JPNvRUS #POTM pic.twitter.com/Ouuku94m28— Rugby World Cup (@rugbyworldcup) September 20, 2019
But you’ve got to take your hat off to the Russian guys because they really took it to us and put us under a lot of pressure.
"Tactically we didn't change a lot. We managed to take the sting out of the Russian offence, they looked a little bit tired and we just managed to execute a bit better and took our chances."
Japan captain Michael Leitch echoed Joseph's sentiments, though believes the Brave Blossoms are now well prepared to face the world's number one side Ireland next up in Pool A.
"Straight away they put us under some extreme pressure with their gameplan and physicality, they really tested us," Leitch said.
✅ Hattrick in the #RWC2019 opener— Ultimate Rugby (@ultimaterugby) September 20, 2019
✅ First 🇯🇵 player to score a hattrick at a RWC
✅ Joint top scorer in RWCs for Japan with 4 tries
✅9 tries in his last 7 games
Korato Matsushima is some form🔥 🔥 🔥 #JPNvRUS pic.twitter.com/h3ldFXCJOn
"There were big nerves, 100 per cent. First game out of the way and we can start looking forward to Ireland.
"I'm happy, we showed great resilience to not go into our shell and keep playing. I think we're in the right spot to take on Ireland."