The former world No. 1 is to face a tougher challenge in the second round against 2017 champion Jelena Ostapenko of Latvia, who knocked out American Madison Brengle 6-2, 6-1.
The 2016 French Open winner said at a press conference on his arrival in Paris that he would "make sure not to make the mistake twice."
Martinez had fielded something approaching his strongest side in the Wanda Metropolitano Stadium and the only conclusion is that perhaps some of them were thinking about Thursday's visit to Sweden to play Malmo.
The transfer window closes on October 5 and Koeman admitted he would like to see another central defender arrive before then.
Wuhan Zall had no chances to enter the championship race after losing to Hebei China Fortune 2-0, while Tianjin enlarged its winless record to 13 games after being defeated by Qingdao Huanghai 3-0 before the match.
Barbosa was forced off with an ankle injury at half-time, and his replacement Henrique took his chance by netting twice in the space of 20 minutes.
Atletico Madrid at home to Villarreal is Saturday's most attractive game, with Luis Suarez likely to start in the Wanda Metropolitano as Atletico looks to improve on its flat showing away to Huesca in midweek.
However the Argentinian giants paid the price for the absence of a cutting edge in attack, registering their second draw from five matches in this season's campaign.
Shanghai led by as many as 35 points in the final period.
Chinese paddlers Fan, Xu Xin, Ma and Lin Gaoyuan are present on the men's singles list. Their main rivals will be Harimoto, Calderano, Mattias Falck of Sweden and Dimitrij Ovtcharov of Germany.
Lautaro's scorcher before the interval wiped out Christian Kouame's opener, and the Argentinian then forced Federico Ceccherini into scoring an own goal seven minutes after the break, helping the Nerazzurri turn around the game.