Here are some notable occurrences.

• 0:57 - Enemy base is missing, probably time to make a few Lotus, if not s Stinger.
• 1:40 - Kingstad has opted for 2x Mason greedy naked expansion instead of making any defenses.
• 1:50 - Two radar dots are scouted.
• 2:00 - Kingstad really begins playing like something is amiss.

The trick was to start playing as if something is amiss as soon as you notice that the enemy base is missing. In this game Kingstad should have been playing defensively from 1:00.

Playing defensively does not necessarily mean making defenses. It probably involves some defenses, but more generally it involves making choices that let you survive against a range of possible immediate threats. Making solid all-rounder units (instead of raiders) can also be a form of playing defensively. Making more constructors and naked expanding is the opposite.

Now, you might say that you will fall behind if you play defensively. This is usually true, but not when you have scouted that your opponent does not have a base. You are ahead economically simply by virtue of having constructed some mexes and solars. Even if, a minute later, you find that your opponent has a non-rushy base in a weird part of the map, the time it took them to walk there probably more than makes up for your defensive play. Of course, once you scout your opponent fully it is time to switch into an appropriate strategy.