'The Ultimate Weapon' Lee Young-ho secured a spot in the semifinals of the Google Play ASL Season 21 after defeating Jang Yoon-chul 3-2 in their quarterfinals match at the FreecUp Studio in Daechi-dong, Seoul, on the 5th, utilizing a strategy centered on timing rushes.

On Match Point, a map known to favor Protoss, Lee opted against Dark Templars and prepared a timing rush following his natural expansion. Jang built a Nexus at his natural and then a third base. Lee launched an attack with a force of tanks, vultures, and goliaths, executing a sharp timing push. However, Jang used his signature shuttle and reaver control to repel the attack and take the first game.

In the second set, Jang attempted a no-gate double Nexus. The vertical spawn positions favored Lee, who scouted Jang immediately. Lee prepared a cheese rush, and after a fierce battle of micro-control, Lee successfully completed a bunker and destroyed the Nexus to gain the advantage. He then secured his natural expansion and used a large tank force to launch a timing attack, evening the series at 1-1.

In the third set on Jane Doe, both players opened by building their expansions in the back. Jang went straight for Carriers without a Robotics Facility, while Lee quickly built a third Command Center and prepared two Armories. Although Jang's Carrier timing was extremely fast, Lee also secured his third base quickly and launched an attack with tanks and goliaths at the 1/1 upgrade timing.

Lee then discovered and destroyed Jang's hidden expansion at the 6 o'clock position, preventing the accumulation of Carriers while continuing to mass Goliaths, moving ahead 2-1.

In the fourth set, Lee again prepared a timing attack. He focused on massing tanks from the start to build up his strength, while Jang planned to defend using reaver control and a third base. Jang managed to pick off several tanks with his Dragoons as Lee's army advanced.

A fierce tug-of-war ensued as the Terran forces established a position at 6 o'clock. Believing he had stabilized, Jang diverted his forces to strike Lee's natural expansion, buying time and eventually overwhelming his opponent with superior numbers to tie the series 2-2.

In the final fifth set, Jang built a Robotics Facility quickly after his natural expansion. Lee gained minor advantages through light harassment and, having identified that Jang was preparing Reavers, focused on his defense. Despite this, Jang managed to harass Lee with his shuttle and reaver while successfully maintaining his third base.

Once again, Lee's decision came down to timing. To avoid repeating previous mistakes, he advanced slowly and cautiously, baiting a reaver control error from the Protoss, which proved decisive. Lee seized the momentum by destroying all of Jang's reavers and his third Nexus. Although Jang defended well with precise control, he could not stop the subsequent waves of Lee's mechanical army. Lee took the series 3-2 to advance to the semifinals, where he will face Lee Jae-ho.