PRAGUE, Jan 21 (Prague) - Former Czech international Jiri Nemec has left Sparta Prague and signed an 18-month contract with their struggling city rivals Viktoria Zizkov, a Sparta spokeswoman said on Wednesday.Nemec, 37, helped Sparta qualify for this season's Champions League by beating Macedonian side Vardar Skopje in the third qualifying round. However, he played in only two group stage matches due to a knee injury. Sparta nonetheless qualified for the knockout stage where they face holders AC Milan. It is the second time Nemec has caused a surprise by joining a more lowly club. Nemec left Germany's Schalke 04 for Czech village team Blsany in 2002 before joining Sparta for the second time in his career. At Zizkov he will be reunited with former Blsany coach Guenter Bittengel who took over during the winter break. Zizkov are second from the bottom in the Czech first division, three points ahead of Blsany and one behind Plzen. A defensive midfielder who played 84 internationals for the Czech Republic, Nemec was part of the Czech team that reached the final of the 1996 European Championship. He also won the UEFA Cup with Schalke in 1997.