Arsenal's business had appeared largely done by the time the window shut on Tuesday night, with Gabriel Martinelli's exit finalised, Gabriel Jesus sealing a move to Barcelona and Ethan Nwaneri heading to Borussia Dortmund on loan.
There had been interest in Atlético Madrid's Julián Álvarez, but no bid ever materialised. It has since emerged the club had at least one more move in motion behind the scenes.
Racing Santander sporting director Chema Aragón confirmed his club edged out Arsenal for García, a 20-year-old right-sided attacker, in a deal worth £4.3m plus a 20 per cent sell-on clause retained by Betis.
"It seemed like it was done with Arsenal, and then we came in too on loan," Aragón said in a press conference on Wednesday.
"On Tuesday things changed, and what seemed to be a loan turned into a shared ownership deal."
Arsenal had reportedly planned to sign García on a permanent basis before immediately sending him out on loan for regular football.
Aragón made clear how highly Racing rate the player.
"I would describe Pablo García as Raúl González Blanco — what he has above all else is a nose for goal, that killer instinct, and he usually puts it away," he said. "My biggest concern was losing that goal-scoring ability for a while after Andrés Martín's injury. When the real opportunity arose to sign that player, we didn't hesitate for a second."
The move brought an emotional end to García's boyhood association with Betis, whom he had represented since the age of six. He made 25 appearances for the first team last season but managed only two goals, struggling for regular minutes under Manuel Pellegrini, and had also been linked with Hull City and Olympiacos before opting to remain in Spain. He is expected to make his Racing Santander debut this weekend.
García reportedly left Betis's training ground in tears after the move was confirmed, having grown up idolising the club.
In a farewell message to supporters, he described the emotional weight of the decision: "I arrived as a Betis fan and I'm leaving as a footballer."
With Betis back in the Champions League this season and needing to balance the books, the sale also helped the club create space to accommodate Dani Ceballos following his arrival from Real Madrid.