Flamengo entered the match with only three regular starters, having reported 16 positive coronavirus cases in their first-team squad last week. Head coach Domenec Torrent was also absent from the touchline at Allianz Parque because of the virus.
The transfer window closes on October 5 and Koeman admitted he would like to see another central defender arrive before then.
31-year-old Sunjic, who stands 1.94m tall, has played for many clubs across Europe, including VfB Stuttgart, S.S.D. Palermo and FC Dynamo Moscow. He also represented his country in the 2014 FIFA World Cup in Brazil.
Ten minutes before the final whistle, Chris Shimbayev fired home after a long run to give Suzhou the three points.
The significance of completing the whole first stage with no one from the closed living and training zone testing positive for the coronavirus cannot be understated. It should be noted that the Dailian Division even faced the threat of a local epidemic outbreak.
Plzen dominated the second half but Beer Sheva came closer to scoring, as Dutch striker Elton Acolatse hit the post in the 68th minute after a run from the halfway line.
In Rio de Janeiro, Vasco da Gama missed the chance to move up to third with a 1-1 home draw against Bragantino.
Tianjin once had a good chance to break the deadlock in the 56th minute when midfielder Che Shiwei was fouled by defender Cong Zhen in the penalty area. After a VAR check, the referee awarded Tianjin a penalty kick, but Ghana's striker Frank Acheampong failed to convert it to a goal.
The Pole had a perfect season to score 55 goals in 47 matches, leading the Bavarians to win the treble of German Bundesliga, German Cup and UEFA Champions League. He was also top scorer in both the Bundesliga and the Champions League.
Facing Shenzhen, Suning's Alex Teixeira smacked the winning penalty in the 28th minute after Li Ang was tripped by Morteza Pouraliganji.
The next race of the 2020 Formula 1 season is the Eifel Grand Prix at the Nurburgring in Germany on October 11. Enditem