Ramos chipped the ball into the middle of the Betis goal to give his side their first win of the season and end Betis' winning start to the campaign.
Beer Sheva scored the only goal after just four minutes of play with a penalty from Portuguese midfielder Josue, after Plzen's goalkeeper Ales Hruska fouled Colombian striker Jhonatan Agudelo.
Roberto Lopez sealed the win in the 94th minute with a powerful shot into the corner after another assist from the impressive Merino.
Elsewhere, Borussia Monchengladbach are still waiting for their first win of the season as they shared the spoils with Union Berlin following a 1-1 draw.
Barca are still working in the transfer market, however, with Ousmane Dembele now linked to a move to Manchester United as the club chases Memphis Depay - a personal request of Koeman's.
It is thought the 41-year-old Baum will act as a mastermind as he stands for the new generation of coaches addicted to innovative tactical approaches.
Mikael Ymer of Sweden returns the ball during the men's singles first round match against Novak Djokovic of Serbia at French Open tennis tournament 2020 at Roland Garros in Paris, France, Sept. 29, 2020. (Photo by Aurelien Morissard/Xinhua)
Omar Al Soma (L) of Al Ahli Saudi FC vies with Abdullah Madu of Al Nassr during the AFC Champions League quarter-final match between Al Ahli Saudi FC and Al Nassr of Saudi Arabia at Jassim Bin Hamad Stadium in Doha, capital of Qatar, Sept. 30, 2020. Al Nassr won 2-0. (Photo by Nikku/Xinhua)
The Men's World Cup list features three consecutive World Championship winner Ma Long, and top-ranked Fan Zhendong, both from China, Tomokazu Harimoto of Japan, Lin Yun-Ju of Chinese Taipei and Hugo Calderano from Brazil.
The game was played behind closed doors at the Menorah Mivtachim Arena in the coastal city of Tel Aviv.
The medals of the women's 200m backstroke were taken by three youngsters. Silver medalist Wang Jiayin from Shandong is just 13 years old. Hubei's Peng Xuwei, 17, bagged the gold in 2:09.02.