I hesitated to post this problem because of the bizarre nature of my partner's 6♦ bid, but the issue is not the bidding, it is the play.
Teams. 12 board match scored at VPs (part of a season long round robin event).
Opponents are fine players. So is partner (despite evidence to the contrary).
After long thought, LHO leads the ♦A, to which all follow, RHO playing the lowest outstanding spot.
After even longer thought, LHO plays the ♥J at trick 2.
Your play?