Racing nerves can blur your focus, but a simple breathing trick helps: breathe...

https://spencersultimatejournals.trexgame.net/is-there-a-quick-routine-i-can-do-in-90-seconds-before-performance

Racing nerves can blur your focus, but a simple breathing trick helps: breathe in for four counts, then out for six to eight. This calms the body and sharpens the mind