The Great Britain para-sprinter set a new 100m personal best at the weekend of 11.24 seconds.
Arnott, a T46 competitor, set his new mark at the Loughborough International Meet in a combined para category race, which saw him finish just behind T44 Olympic champion Jonnie Peacock and T12 competitor Zac Shaw.
He then followed that impressive time up with his second fastest legal 100m of all-time on Wednesday evening at Lee Valley Summer Series Sprints Open.
Arnott ran 11.31 seconds in that competition.
The previous week, the under-23 world champion had won gold in the 100m and 200m events the Miting International in Spain.