The result at more than 3,600m above sea level in Bolivian capital La Paz meant Palmeiras now have three wins from as many matches to hold a six-point lead over Guarani, who are second in the group.
Bremen needed 30 minutes to gain a foothold into the game as Joshua Sargent tested Alexander Scholow with a long-range effort.
Hoffenheim dominated possession and produced more promising chances but Horn was on guard to deny Kramaric and Pavel Kaderabek in the 18th minute.
A second equalizer by Vagner Love in the 80th minute was disallowed by Danish referee Mads-Kristoffer Kristoffersen due to a controversial offside decision and the hosts kept their lead until the final whistle.
"I'm always proud to wear my colors. Thank you, Pumas, for trusting me and being my support," Talavera, who has been capped 28 times, said in a Twitter post.
The Gunners only finished eighth in the Premier League last season, but their FA Cup win secured them a place in the UEFA Europa League for the 2020-21 campaign. Enditem
Zinedine Zidane's side didn't play in the first round of matches one week ago, after their game at home to Getafe was postponed in order to allow them more time to recover after their participation in last season's Champions League in August.
Having run away with the 2019-20 Premier League, Liverpool started the new campaign in a similar fashion, with talismanic attacker Mohamed Salah opening the scoring from the penalty spot after just four minutes following a handball from Leeds defender Robin Koch.
Dominik Greif, the man guarding the visitor's goal on the opposite end, erased the home team's greatest scoring chance in a similar manner in the 81st minute after a square pass attempt.
In Chilean capital Santiago, Colo-Colo defeated Uruguay's Penarol 2-1 while Brazil's Santos were held to a goalless home draw by Paraguayan side Olimpia. Enditem
Both Bale and Reguilon are expected to take their medicals at the training ground with their contracts expected to be made official later in the day.