Real Madrid beat Arsenal in a penalty shootout after Gareth Bale had made a goalscoring return to the Spanish side in a thrilling 2-2 draw at the International Champions Cup on Tuesday.
The Spanish club suffered an injury scare as Marco Asensio had to been stretchered off the field in the second half after a knee injury.
The match looked to be over as a contest after Real defender Nacho was sent off for two yellow cards in a frantic early spell at FedEx Field outside of Washington, D.C.
Lacazette stepped up to sneak the 10th minute penalty home, before the Frenchman delightfully flicked the ball through for Pierre-Emerick Aubameyang to double the lead 14 minutes later.
The referee evened things up, however, when he again brandished two yellow cards in quick succession to send Arsenal's Sokratis Papastathopoulos from the field in the 40th minute.
Welshman Bale and Asensio scored inside three second-half minutes to level up the score and take the game to penalties.
"We are a bit worried, it is the knee," Real Madrid boss Zinedine Zidane said of Asensio's injury after the game."He went directly to the hospital for tests. It didn't look good. It's the bad part of the day for us because we lost a player and we are a bit affected."
Arsenal edged in front in the shootout when Reiss Nelson scored his spot kick and Bale missed his, but misses from Granit Xhaka, Nacho Monreal and Robbie Burton proved costly and Real ran out 3-2 winners.
Arsenal return to England having narrowly missed the chance to finish their U.S. tour with a 100% record, but can take plenty of positives from their four matches.
"We finished today, the last match, with the same spirit we played before," Arsenal manager Unai Emery said. "We used different players and took minutes and confidence.
"The result isn't important but we showed a good level and when we needed young players their performance was perfect.