Albirex Niigata (S) all but sealed their second successive S.League crown after easily dispatching Balestier Khalsa 3-0 at Toa Payoh Stadium on Thursday night.
First-half goals from Tsubasa Sano and Hiroyoshi Kamata put Albirex in the driving seat, before Ryota Nakai scored late on to put the White Swans on 56 points with two games remaining.
Nearest challengers Tampines Rovers can reach the same number of points if they win their final three games, but should still lose out due to inferior goal difference -- +20 compared to Albirex's +45.
Third-placed Home United are officially out of the mix as they can reach a maximum of only 55 points.
Despite the win that has effectively sewn up the title, Yoshinaga was less than overjoyed at the post-match media conference.
"The title is still not 100% confirmed," the former Shimuzu S-Pulse coach said. "We still have a target of 60 points to hit.
"Tonight, I thought the players dropped in their accuracy in passing. There were a lot of misplaced passes and we could not up the tempo when we wanted.
"This level of performance is not good enough. A lot of them are first-year professionals; if they want to be professional players for a long time, they have to work hard in each game.
"There's still two more games before we play the Singapore Cup final, and the players will need to play well to ensure their starting places."
Albirex sounded a warning sign on 10 minutes, with Sano forcing Zaiful Nizam to save with his legs before Ryota Nakai fired wide on the rebound.
Balestier failed to heed that, and conceded the opening goal three minutes later.
Nakai's reverse pass took out the entire Tigers defence, before Sano fired home a clinical finish past the onrushing Zaiful for his 19th league goal of the season.
It could have been easily 2-0 just moments later, but Zaiful did superbly to deny Nakai from point-blank range.
Balestier gradually steadied the ship and came close to levelling matters on 31 minutes, but Fadli Kamis was unable to keep his header from Raihan Rahman's free kick on target.
Albirex would show them how it should be done five minutes before half time.
Kamata rode a couple of challenges before lashing a powerful drive from the edge of the box, which Zaiful got two hands to, but could not keep out.
Marko Kraljevic's side could have pulled one back on 43 minutes, but Aung Kyaw Naing's well-directed header on Sheikh Abdul Hadi's cross was tipped wide by Yosuke Nozawa.
At the other end, Albirex were denied a third goal on the stroke of half time with Yasutaka Yanagi's header coming back off the post.
The White Swans took their feet off the pedals in the second half, but Balestier was still unable to find a breakthrough.
Midfielder Huzaifah Aziz did have a good attempt from 25 yards out in the 62nd minute, but the effort flew wide of the left-hand post.
Yoshinaga's charges went on to seal the win a minute from time, with Nakai volleying past a stranded Zaiful after Sano's shot had come off the bar.
Balestier will now need to look over their shoulders for seventh spot, as they are just two points ahead of Brunei DPMM, having played two games more.
While disappointed with his side's display, Kraljevic lauded his opponents for their imminent S.League success.
"Albirex changed their style of play today, with long balls to their wingers and strikers," the German-Croatian said.
"We were not expecting that and we struggled with their movement. We have studied how they play, but lapses in concentration meant they could just punish us.
"We're playing against the likely champions and we can always learn something from them. I believe everyone should learn from them and if we do so, Singapore football can improve a lot."
Balestier Khalsa: Zaiful Nizam (GK, C), Fadli Kamis, Hanafi Salleh, Sheikh Abdul Hadi, Ahmad Syahir, Tajeli Salamat, Huzaifah Aziz, Raihan Rahman (Shah Hirul 79'), Nanda Linn Kyaw Chit, Hazzuwan Halim (Rafiqin Kamal 66'), Aung Kyaw Naing (Fariz Faizal 79')
Albirex Niigata (S): Yosuke Nozawa (GK), Tomoki Menda (Rui Kumada 88'), Yasutaka Yanagi, Takuya Akiyama, Naofumi Tanaka, Shoichiro Sakamoto (Ryuya Motoda 58'), Shuto Inaba (C), Hiroyoshi Kamata (Yuuki Yamanouchi 61'), Kento Nagasaki, Ryota Nakai, Tsubasa Sano