Well since it's a Google acc (G+) before you do anything with your FB acc:
1. Open Top 11 on your mobile device.
2. Go to Settings > Accounts tab to the right
3. Tap the Connect button on the G+ row
- If there is only one G+ acc on your device, the link should just complete.
- If there is more than one G+ acc on your device, the game will prompt you to chose one of the accs.

And that's it!

To test it out you can logout the FB account from the FB app on your device, then open Top 11 and when the game doesn't find the FB account in question, it should bring your to the Log-in menu. Chose the Google option for login and then the appropriate G+ acc (If there is more than 1).