Chelsea face a nervy wait ahead of their crucial round of 16 second-leg clash against Paris Saint-Germain in the Champions League after UEFA launched a formal investigation into Pedro Neto for "unsporting behaviour". The Portuguese winger, who has contributed 10 goals in 42 appearances this season, is facing a potential suspension following a heated stoppage-time incident where he shoved a ball boy during the Blues' 5-2 first-leg defeat. Chelsea winger Neto is facing a potential suspension for the second leg of the tie. European football's governing body confirmed on Thursday that it has opened an investigation into the Portuguese international's conduct during the first leg at the Parc des Princes. A UEFA statement said: "Disciplinary proceedings have been instigated against Pedro Neto for unsporting behaviour. UEFA's disciplinary bodies will take a decision on this case in due course."The incident occurred late in the game as Chelsea were trailing 4-2 on the night, eventually falling to a 5-2 defeat. Frustrations boiled over in stoppage time when Neto, desperate to restart play, forcefully shoved a ball boy in the chest, sending the youngster tumbling. The act sparked a mass altercation on the touchline involving players and staff from both benches, leaving a sour taste on what was already a miserable night for the Premier League side in the French capital.The 26-year-old winger attempted to make amends immediately after the final whistle. Neto tracked down the youngster to offer a personal apology and even handed over his match-worn shirt as a peace offering. He later explained that his international team-mate, Vitinha, acted as an interpreter to ensure the message was received. "Straight away I spoke to him and he laughed, he was happy I gave him the shirt and I said sorry like 35 times," Neto revealed.Speaking to TNT Sports, the former Wolves man was visibly shaken and insisted the outburst was out of character. Neto told the broadcaster: "I want to apologise. I already spoke with him. It was the heat of the moment. We were losing, and I wanted to pick up the ball. I gave him a little push, and that cannot happen. I saw that I hurt him; I’m not like this… it was in the heat of the moment; I gave him my shirt. I have to apologise to him. I’m really, really sorry about that."Chelsea manager Liam Rosenior also addressed the situation, acknowledging that the emotions of a high-stakes European knockout tie had got the better of his player. The Blues boss was keen to ensure the club's image remained intact despite the flashpoint. "If there was anything from our side that was wrong or out of order, I apologise on behalf of the club," Rosenior said.Rosenior's side now has a mountain to climb in the return leg at Stamford Bridge, and they may have to do it without one of their primary attacking threats. Neto has been a key figure for Chelsea this term, netting 10 goals in 42 appearances across all competitions. A suspension would be a hammer blow to their hopes of overturning the three-goal deficit against a rampant PSG side featuring Ousmane Dembele and Khvicha Kvaratskhelia.Add GOAL.com as a preferred source on Google to see more of our reportingThe disciplinary headache comes at a pivotal moment for Chelsea as they juggle European ambitions with a tight race for the top four in the Premier League. Currently sitting fifth in the table, the Blues remain level on points with Liverpool and just three points behind Manchester United and Aston Villa. The pressure is mounting on Rosenior to deliver Champions League football for next season, and incidents like Neto's only add to the scrutiny surrounding the squad.The club must now wait for UEFA's final verdict to see if Neto will be available for next Tuesday’s showdown in London. Before that, Chelsea must refocus for a crucial domestic clash against Newcastle.