Complex sentence: Racing at Lima, Peru's Hipodromo de Montericco, Tomcito won his debut race in such impressive fashion that his handlers decided to enter him in the September 23 Group One Clasico Polla de Potrillos (Peruvian 2000 Guineas).
Split into simpler sentences: Racing at Lima, Peru's Hipodromo de Montericco, Tomcito won his debut race. His handlers then enterer him in the September 23 Group One Clasico Polla de Potrillos (Peruvian 2000 Guineas).