* Beat Nacional 1-0 for 2-1 aggregate win
* Win record 23rd title for Argentine clubs
* Qualify for Club World Cup in December (Adds quotes, detail)
By Luis Ampuero
BUENOS AIRES, Aug 13 (Reuters) - Nestor Ortigoza scored the most important penalty in San Lorenzo's 106-year history as the Argentine side won South America's Libertadores Cup for the first time with a 2-1 aggregate victory over Paraguay's Nacional on Wednesday.
Midfielder Ortigoza's first-half spotkick gave San Lorenzo a 1-0 home win after the teams, who had never before reached the final, drew 1-1 in the first leg in Asuncion last week.
'The Saints', who qualified for the Club World Cup with the win, have finally managed to shake off the tag of being the only one of Argentina's 'Big Five' never to have won the trophy.
"They put their trust in me and I thank them for that," Ortigoza told Fox Sports of his coach and team mates.
The victory also gave Argentina a record 23rd title in South America's top club competition since it was first played in 1960. It was also the first time in five years that it was not won by a Brazilian team.
A Paraguayan side finished runners-up for the second year in a row after three-times champions Olimpia lost to Atletico Mineiro in 2013.
"We played a very poor first half, the team were very nervous, tense, they were affected by the expectations of the crowd, but luckily we won," Edgardo Bauza told Fox Sports.
It was Bauza's second Libertadores success after steering LDU Quito to Ecuador's first title in 2008.
That success persuaded the San Lorenzo board to appoint Bauza after league-winning coach Juan Antonio Pizzi quit in December to take charge of Valencia.
The competition, which began with a preliminary knockout round at the end of January, ended with the new season already underway having been held up for two months between the quarter-finals and semi-finals of the World Cup in Brazil.
It had been a struggle for San Lorenzo to keep key players in their squad as some of them were out of contract by the end of June.
Attacking midfielder Ignacio Piatti was granted permission by his new club, Montreal Impact of the MLS, to play up to the first leg of the final but he was absent for the second leg on Wednesday.
Nacional started brightly and came close in the first minute when San Lorenzo midfielder Juan Mercier lost the ball inside the box and Derlis Orue fired against the post.
San Lorenzo replied with a long range drive from right back Julio Buffarini that went over the bar before Nacional midfielder Silvio Torales forced Saints goalkeeper Sebastian Torrico into a difficult save in the 18th minute.
San Lorenzo were struggling to find some rhythm in the face of Nacional's quick counter-attacks but were awarded a penalty in the 36th minute when defender Ramon Coronel handled the ball.
Ortigoza made no mistake from the spot, blasting the ball home as Nacional goalkeeper Ignacio Don dived the wrong way.
The goal, celebrated wildly by the Saints fans in a crowd of more than 40,000 at a packed Nuevo Gasometro, gave San Lorenzo the impetus and they pinned Nacional back for the remainder of the first half.
The home side began finding more space in the second half as Nacional took greater risks at the back in search of an equaliser, with visiting midfielder Marcos Riveros coming close in the 65th minute and striker Fredy Bareiro in the 78th.
San Lorenzo fans have attributed their success to the anointing last year of Argentine-born Pope Francis, a fan and club member, winning the league title in December and now the South American crown. (Writing by Rex Gowar; Editing by Peter Rutherford)