After having provided correct credentials, instead of having been granted access to my Google account, I was instead redirected to a landing page telling me this:

    Couldn’t sign you in
    This browser or app may not be secure. [Learn more]
    Try using a different browser. If you’re already using a supported     browser, you can try again to sign in.

Only after having read through that that I noticed an innocent "Try again using this browser"-link on the aforementioned landing page, which made me authenticate a second time using the very same credentials, and then, finally, letting me into my Google account.

I guess that's a new way to try shoving Chrome down even more peoples' throats?

It's high time anti-trust regulators slap the sh*t out of this corporation for its increasingly hostile tactics, similar to how the US set out to do with Microsoft back in the 90s.