Naomi Osaka cut a frustrated and dejected figure following her heartbreaking loss to 18-year-old home favorite Victoria Mboko in the women's singles final of the 2025 National Bank Open in Montreal, Canada. Osaka kept her post-match speech short, but controversially neglected to congratulate Mboko for winning the WTA 1000 hardcourt event. Subsequently, several tennis fans criticized the former No. 1 and four-time Major champion.The Japanese put herself in pole position for clinching the trophy by winning the first set 6-2. However, Mboko stormed back in the second set, clinching it 6-4 to take the match into a decisive third set. Osaka then visibly lost her cool on more than one occasion while the Canadian kept her nerve, winning the set 6-1 to win her maiden WTA Tour-level title.Choosing to keep her post-match speech short, Naomi Osaka said:"Thanks, I guess. I don’t really want to take up too much time. I’ll just say thank you to everyone. Thank you to my team, the ball kids, organizers, & volunteers. I hope you guys had a good night."Osaka's decision to not congratulate the newly-crowned National Bank Open women's singles champion didn't go down well with tennis fans on X (formerly Twitter). One fan brought up what the Japanese said about facing Mboko in the final at her post-semifinal press conference."It’s absolutely shameful that Naomi Osaka knows that Victoria Mboko idolizes and look up to her, and she couldn’t even congratulate her or even mention her name.Disgusting, sore loser behaviour. She earned a hater in me today," the fan wrote.The fan was referring to the following quotes from the former No. 1's presser, where she talked about going up against a much younger player who previously confessed to idolizing the Japanese:"I guess I have to have a really good attitude tomorrow. I can't let her not like me anymore. I don't know, it's funny because I was, like, I see her on the TV, and I was low-key, like, That's my little twin, because we both have our blue dresses and our buns and everything. I mean, I'm really honored."Several other fans chimed in with criticism of the four-time Slam winner for snubbing Mboko."Oh Naomi u so weird you couldn’t say some positive words to the girl?," asked one."Naomi not even saying a word about vicky during her speech really rubbing me the wrong way :/ like i get you’re very upset and don’t want to be there but come on!??? makes it worse that vicky thanked her and said she looked up to her too😭😭," another added."So Mboko literally grew up idolozing Osaka, Osaka starts crashing out during the game (shooting the ball into the audience) and then she couldn’t even have the stomach to congratulate Mboko for winning? Low to say the least," one fan opined."What a treasure Canada has with Vicky Mboko astonishing women’s National bank tournament tennis championship win tonight in Montreal. On the flip side, what an embarrassment from Japan, Naomi Osaka was a sore loser and gave a pathetic consolation speech. Arrogance and contempt," yet another fan chimed in."How about “congratulations” Victoria!!!…wow, completely classless," weighed in one more fan.Victoria Mboko reiterated her admiration for Naomi Osaka in her Canadian Open winner's speechVictoria Mboko (left) delivers her speech after defeating Naomi Osaka (right) in the women's singles final of the 2025 National Bank Open (Source: Getty)Despite Naomi Osaka's refusal to acknowledge Victoria Mboko, the 18-year-old reiterated her admiration for the former No. 1 during her own speech. Displaying undeniable class and maturity, the teenager said:"I want to thank Naomi for an incredible match. I’ve always looked up to her when I was really little. It’s great to play with such an amazing player like you."Naomi Osaka and Victoria Mboko's runs at the 2025 National Bank Open have significantly boosted their respective WTA Tour-level singles rankings. Osaka is now up to World No. 25, while Mboko is just ahead of the Japanese at No. 24. Remarkably, the 18-year-old began the ongoing tennis season ranked No. 333. Both players are set to now turn their attention to the WTA 1000 event at the Cincinnati Open.