Inaba stunner puts Albirex in driving seat
Balestier Khalsa put up a strong fight against their more illustrious opponents, especially in the first half but failed to put away a couple of good chances.
Apart from a Kazuki Mine header that came off the crossbar, it was the Tigers that threatened.
First Miroslav Kristic broke free in the box after Kento Fujihara failed to cut out Shah Hirul's ball, but the Croatian dragged his shot well wide.
Then Shah Hirul saw his rasping volley well held by Albirex Niigata (S) custodian Eita Kasagawa.
It looked like they had done enough to go into the break all level, only to be denied by a world-class goal by Albirex captain Inaba in the 44th minute.
The ball fell to the 23-year-old on the edge of the area after Balestier goalkeeper Zaiful Nizam had punched clear Kento Nagasaki's free kick and he needed no invitations to lash home a stunning first-time volley into the top right corner.
Balestier were forced to make a substitution at half time with Hazzuwan Halim replacing Niko Tokic, who got a slight knock on his knee.
That meant Kristic was left alone upfront without much proper service.
By contrast, Albirex dominated much of the proceedings and could have been two to three goals up.
Rui Kumada prodded over from six yards out after an excellent Naofumi Tanaka cross, then Tomoki Menda's volley from an acute angle was tipped wide by Zaiful.
Substitute Masaya Jitozono came the closest in the 88th minute with a superb 20-yard free kick, but Zaiful was equal to the task once again.
Balestier almost nicked a draw right at the end with substitute Sadin Smajovic finding space just outside the area, but his curling effort was parried to safety by the alert Kasagawa.
Speaking at the post-match press conference, Albirex coach Naoki Naruo gave credit to the solid Tigers defence for keeping the score down.
"It was a difficult game and we did not create so many chances because Balestier were making solid blocks," said the 41-year-old. "It was great for us to score from middle range against a team that made so many blocks."
Meanwhile Balestier coach Marko Kraljevic accepted that his side was defeated by an unstoppable strike, but is determined to come back strongly in Tuesday's second leg at Toa Payoh.
"I can see the ball going in once it fell on his (Inaba's) feet, nobody can stop that one," lamented the German-Croat. "We played well and have a few good chances in the first half, but the boys did not convert.
"But we still have 90 minutes to go. Playing at Toa Payoh gives us the slight advantage and there's not much to calculate. We have to win (to progress into the final)."