Returning to club duties, with Zdrilic out injured for much of the season due to the knee injury he sustained on international duty, Ulm had been relegated back to the second division and Zdrilic sought to remain in the top league. Despite the injury Zdrilic scored 6 goals in 13 Bundesliga starts for Ulm and moved to SpVgg Unterhaching. The club struggled for consistency through the 2000–01 season and was eventually relegated, Zdrilic remaining with the club on its return to 2. Bundesliga. Haching continued to struggle for results in the 2001–02 season, relegated again at the end of the year. In contrast to club fortunes, Zdrilic was achieving greater success at international level throughout this time. Becoming a regular inclusion in an Australian side under Frank Farina, he was recalled for a friendly against Scotland to replace the injured Mark Viduka scoring in a memorable 2–0 victory at Hamden Park. He retained his place in the squad for the Oceania World Cup qualifiers. In Australia's second match of the tournament, he scored eight goals in a world record 31–0 win over American Samoa. He and his strike partner Archie Thompson, who scored 13 goals, broke the record for most goals scored in a senior international match. He remained in the team for the 2001 FIFA Confederations Cup, taking part in the Socceroos memorable victories over Mexico and Brazil.