Newell's Old Boys beat Paraguayan side Olimpia 3-1 to get their Copa Libertadores Group Seven campaign off to a winning start.
Things were tense in Argentina until the 69th minute when striker Ignacio Scocco finally broke the deadline from the penalty spot, then youngster Horacio Orzan doubled the advantage six minutes later.
Freddy Bareiro reduced the deficit with a header in the 87th minute, but former Liverpool midfielder Maxi Rodriguez consolidated the victory with a minute to go.
Newell's join Universidad de Chile at top of the group after the Chilean side saw off Venezuela's Deportivo Lara 2-0 on Tuesday.
"Olimpia did not sit back, but pressured us. It was a fair win because we always tried to score," Newell's coach Gerardo Martino said.
Chilean champions Huachipato shocked Gremio in Brazil as they won 2-1. Braian Rodriguez was the man of the match with a goal and an assist to help Huachipato hit the top of Group Eight.
Uruguayan forward Rodriguez first assisted Federico Falcone, who opened the scoring in the 16th minute, then received the ball from Jose Contreras and headed the ball into the net in the 51st.
Gremio's recent signing Hernan Barcos scored a penalty to reduce the deficit but it was in vain.
"We are completely proud," Huachipato boss Jorge Pellicer said. "We dedicate this win to all the fans who supported us in Chile. That is why Huachipato were league champions. The final score makes me very satisfied because it reflects what happened on the field."
In Group Three, Bolivian side The Strongest saw off nine-man Arsenal of Argentina 2-1.
Alejandro Chumacero put the hosts ahead in the 17th minute and, though Dario Benedetto equalised three minutes after the interval, Luis Melgar gave The Strongest the win with seven minutes to go.
In La Paz, at 3,600metres above sea level, Arsenal ended the match with two men fewer as midfielder Damian Perez and forward Emilio Zelaya were shown red while the game was tied.
Group Two opened with a 2-1 win for Brazilian giants Palmeiras over Peruvian champions Sporting Cristal.
Henrique and Patrick netted the winning goals, one on each half, while Carlos Lobaton scored a penalty for Cristal.
The first week of the group stage closed with Tolima celebrating a 2-1 win over visitors Cerro Porteno of Paraguay in Colombia.
An own goal by Luis Cardozo gave Tolima the lead after 31 minutes and David Silva made it 2-0 in the 58th.
Nerves increased when Williams Martinez headed the ball and reduced the gap in the 77th minute, but Tolima finally held on to win in Group Six.
Information from the Press Association was used in this report.