"We have to improve in order to be able to compete in the league with guarantees," added Dutchman.
"We are working hard for the new season and I think we will have the same group of players that we have now in pre-season," he commented.
The pre-season has helped clear up some issues at Real Madrid, with Gareth Bale and Sergio Reguilon in London ahead of their planned moves to Tottenham Hotspur, while Brahim Diaz has joined AC Milan on loan.
Koeman had expressed an interest in signing Dutch international Memphis Depay from French side Lyon, but in a TV interview on late on Tuesday, he explained that Barca's economic situation was complicating the deal.
In the 28th minute, thanks to a short cross from Cedric Bakambu on the midfield, Renato Augusto dribbled through defender Ding Haifeng and contributed a calm tap-in to pull one back.
The 87-year-old Senegalese was sentenced to two years in prison, with another two years suspended. The court also imposed a fine of 500,000 euros (about 592,500 U.S. dollars) on Diack.
In other action on Sunday, Jamie O'Neill took top spot in his group after two wins and one loss.
"It [a return to international football] is a wish and a goal. I want to take it game-by-game and if the opportunity arrives I will be very happy. If it doesn't, I'll continue working hard so that I can be considered."
New Betis coach Manuel Pellegrini made his presence felt as his side defended much better than they did last season in their 1-0 win away to Alaves last week, while Valladolid were slightly unlucky to only draw 1-1 at home with Real Sociedad.
Khalid Al-Ghannam (R) of Al Nassr FC vies for the ball with Seyed Mohammad Karimi of Sepahan FC during the AFC Asian Champions League group D football match between Al Nassr FC of Saudi Arabia and Sepahan FC of Iran at Jassim Bin Hamad Stadium in Doha, Capital of Qatar, September 15, 2020. (Photo by Nikku/Xinhua)
RIO DE JANEIRO, Sept. 15 (Xinhua) -- A dramatic stoppage-time goal from substitute Walter da Silva gave Brazil's Athletico Paranaense a 3-2 away victory over Bolivian side Jorge Wilstermann as the Copa Libertadores resumed from a six-month coronavirus hiatus on Tuesday.