I would just use INVITE e.g. I posted Invite yesterday.
Invtl
INVTL
Invitational Tournament.
Pasco Invitational was created in 1962.
The Style Invitational was created in 1993.
Chicago Invitational Challenge was created in 2007.
Eastern Open Invitational ended in 1962.
Eastern Open Invitational was created in 1950.
Women's Basketball Invitational was created in 2009.
Golden West Invitational was created in 1960.
Hawaiian Islands Invitational was created in 2011.
Newport Casino Invitational ended in 1967.