Temuco (Chile), June 26 (IANS): Bolivia coach Mauricio Soria admitted that Bolivia changed their system to no avail in their 1-3 Copa America football quarter-final defeat to Peru after striker Paolo Guerrero scored a hat-trick to eliminate them.

The frontman netted a first-half double before wrapping up the win with a strike in the second half on Thursday.

Soria told the press after the game that Bolivia had planned specifically with a five-man backline for the 31-year-old and his strike partner, Claudio Pizarro.

"Our opponents' style of play meant we had to pay attention to their two great attacking players," he said.

"They were instrumental in determining our change of plan. We had a tactical intention that we didn't carry out on the goals. They hit us on the counter."

"They took advantage of their chances but in the second half we were the better team," he added.

Bolivia reached the last eight for the first time since finishing runners-up to Argentina on home soil in 1997 and Soria admitted that the nation had work to do in order to keep pace with their South American rivals.

"We have to work a lot tactically and physically," he said.

"However, we also need better infrastructure and that the local league becomes stronger. The players do not last long in our country."