No.  You do not need a PayPal account to checkout using a credit card.
On the checkout screen select "Purchase with a Credit Card or PayPal." and then press the "Pay with CREDIT CARD USING PAYPAL.COM" button.
This will bring you to the PayPal site.   You do NOT need to login here.  Towards the button Select "Pay with Debit or Credit card” this will allow you to check out as a guest on the PayPal site.