Londonderry's Jordan Coyle excelled in the Palm Beach Masters qualifier in the United States, while Saintfield rider Conor Swail was also in the spotlight.
Coyle partnered Eristov to win the 1m $89,000 (£72,595) Palm Beach qualifier, while Swail, with GK Coco Chanel, finished runner-up in the $135,000 (£110,000) five star Palm Beach Masters Classic.
Coyle admitted winning wasn't part of his original plan. He explained: "We had a few hiccups this season and this class wasn't normally for Eristov. The main Masters would have been his class but with everything that's happening, I thought I should try to win."
From 56 entries, 22 horses made it to the second round, with Coyle recording a winning time of 67.27 seconds ahead of GB's Ben Maher and Explosion W, who went clear in 68.63.
The rosette for third went to the Republic of Ireland's Billy Twomey and Lady Lou, clear in 69.62.
Swail produced an impressive performance when last to go in the 13-rider Masters Classic jump-off.
The event was won by GB's Emily Moffitt on Tipsy Du Terral, clear in 38.20. After steering GK Coco Chanel into runner-up place in 38.57, Swail collected a cheque for $27,400 (£22,349).
Darragh Kenny, meanwhile, continued his top form to win the $137,000 (£111,000) Horseware Ireland three star Grand Prix with Scarlett Du Sart Z from 45 starters, while Bertram Allen took the 1m45 two phase with Lafayette Van Overis.
Ulster riders based in the US will remain there after a number of events were cancelled due to the coronavirus.