The first set was dominated by the world No. 13, but Cirstea hung tough in the second and pinched it in the tiebreak. After that, Cirstea never looked back.
The re-appointment of Simiyu brought an end to speculation over who would take over the team that has struggled in the HSBC World Rugby Sevens Series since he left.
"For me it is a dream come true to play in a big club like Chelsea and I can't wait to meet all the players and the trainers. Yeah," said the 21-year-old, who arrives from Bundesliga club Bayer Leverkusen.
In the other two matches of the day, Hunan Hualai edged Shenzhen Nankeda 3-2, while Olympic champion Chen Long led Xiamen Tefang to a win over Anhui Souyu 5-0. Enditem
"I got a slipstream, found a gap and timed my sprint perfectly," he said. "But this is more of a surprise than the last win."
Awaiting him in the next round is 20th seed Pablo Carreno Busta of Spain.
"They feel that what is happening with the U.S. Government could create a negative precedent internationally that could be replicated and would jeopardize the entire global anti-doping system."
It's the second straight victory for Portugal, as they defeated Croatia 4-1 at home last Saturday. They will visit France in October in their third match in Group 3.
The home side was seen as lacklustre in the encounter with Greece, but managed to pick up the pace against the much lower ranked Moldova after coach Matjaz Kek made a few changes to the starting line-up, according to the Slovenian Press Agency STA.
"The female Iranian players have to wear a hijab or a head cover. In the beginning, it was difficult because there were no leagues who accepted us. However, the Bulgarian federation opened its doors to Iranian women and confirmed our participation in their league," said Borhani.
"I was a little bit in shock," Carreno Busta said. "The rules are the rules. The referee and the supervisor did the right thing, but it's not easy to do it."