Move first item of secondary nav to opposing side

Hello team!

I have a secondary navigation above the header and the items are positioned on the right side.
The first menu item would need to be positioned to the left side like in the example shown here:

https://i.stack.imgur.com/D3Vnv.png
(Full post at: https://stackoverflow.com/questions/32551291/in-css-flexbox-why-are-there-no-justify-items-and-justify-self-properties/33856609#33856609))

I tried this out by adding:

#menu-item-1053 {
	margin-right: auto;
}

However it does not seem to work and my flexbox knowledge is failing me.
Any tips would be greatly appreciated!

Thank you,
Alexander