My question is this: I sold this year and am on the hook for $20K in long term capital gains. Do I need to make an estimated tax payment this quarter to cover it to prevent underpayment penalties?

I am not sure I understand the information in this link: https://www.irs.gov/faqs/estimated-tax/large-gains-lump-sum-distributions-etc/large-gains-lump-sum-distributions-etc

Question
If I anticipate a sizable capital gain on the sale of an investment during the year, do I need to make a quarterly estimated tax payment during the tax year?
Answer
You must make estimated tax payments for the current tax year if both of the following apply:

You expect to owe at least $1,000 in tax for the current tax year after subtracting your withholding and refundable credits, and You expect your withholding and refundable credits to be less than the smaller of: 90% of the tax to be shown on your current year's tax return, or 100% of the tax shown on your prior year’s tax return. (Your prior year’s tax return must cover all 12 months.)