The 33-year-old Olympic champion, using his trademark late surge, clocked 13.13 to claim victory over the USA's Daniel Roberts, who was among the early leaders. The American clocked 13.15 in the blanket.
Wilhem Belocian of France crossed the line third in 13.30.
Seville, who clocked 10.88s for fourth place in the 100m final in Budapest, clocked 10.04 finishing just behind Kenya’s Ferdinand Omanyala, who won in 9.94.
Italy’s Lamont Marcell Jacobs finished third in 10.08.
Jamaican 100m champion Rohan Watson was seventh in 10.32.
The two-time World Championship silver medalist produced a lifetime best of 15.01m in Brussels but needed only 14.53m for victory in Croatia.
Ricketts was almost a half-metre better than Italy’s Dariya Derkach, whose best jump of 14.07m earned her second place. Ricketts’ Jamaican compatriot Kimberly Williams, who has struggled to jump 14m for most of the season, could only manage a 13.70m effort which was good enough for her to finish third.