The 25-year-old, who spent last season on loan at Albion chairman Tony Bloom‘s Belgian team Royale Union Saint-Gilloise, played a key part in booking the Samurai Blue’s place at the showpiece event, which kicks off on November 21.
Mitoma turned March’s Asian qualifying Group B match against Australia on its head after being introduced with six minutes of the game remaining.
The winger’s 89th minute opener was a close-range effort from the six-yard box, while his second was a fine individual strike that was too powerful for Aussie keeper and former Seagulls star Maty Ryan.
The 2-0 win guaranteed Japan a top-two finish in Group B and sealed a seventh consecutive FIFA World Cup appearance.
Speaking to The Japan Times, Mitoma said: “(The goals against Australia) were significant for both me and Japan.
“I felt it was crucial to get the result, and that was what drove me.
“I’ve thought of myself as the type who is good in big moments, so I’m glad I was able to deliver there.”
He added: “I always aim to be in the starting line-up. Since there are only a small number of international games, chances are limited. If I can help get results in the games I start, things might change.”
“I have a chance (at World Cup selection) and I absolutely want to make it. I’m not sure how much more I can strengthen my case before November. All I can do is keep improving my skills.”
Check out the latest Premier League transfer speculation below...
1. Saints lead Pope race
Southampton are favourites to sign Burnley goalkeeper Nick Pope ahead of Fulham and West Ham. (SkyBet)
2. Villa drop Tarkowski interest
Aston Villa have reportedly dropped their interest in signing Burnley centre-back James Tarkowski this summer. The defender is also a target for Everton. (Express and Star)
3. Gunners keen on Tielemans
Arsenal are still interested in Youri Tielemans, with the player set to leave Leicester City this summer. (Fabrizio Romano)
4. Leeds eye Kristensen
Leeds United face a £10m transfer battle with Borussia Dortmund and Brentford for Denmark international right back Rasmus Kristensen. (Daily Mail)