Tadjiyev put the cup holders one up after 17 minutes before doubling the lead 18 minutes from the final whistle to give Pakhtakor a comfortable two-goal cushion for the second leg on August 2 in Tashkent.
Pakhtakor have won every Uzbekistan Cup final since 2001, defeating AFC Champions League 2008 quarter-finalists Kuruvchi on penalties to win the competition for the seventh year in a row.