Jessica Pegula and Emma Navarro will go head-to-head in an all-American quarterfinal at the US Open Tuesday night.Not only will it be the first time two American stars will clash in the last eight since 2015, but it will also be a match-up that boasts some serious family worth.Navarro and Pegula will meet in an all-American US Open QF on TuesdayGettyA total of $15 billion, to be exact.How much are the Pegula and Navarro families worth?Pegula, the current World No. 3, is the daughter of Terry Pegula. The American businessman and petroleum engineer made a fortune in oil and gas, and has since turned that into a sports empire that includes the Buffalo Bills and Buffalo Sabres.His NFL franchise has recently opened a new $2.1 billion stadium, although it hasn’t been without its flaws.Pegula’s oil and gas outfit, East Resources, sold the bulk of its assets to Royal Dutch Shell for $4.7bn in 2010.He then bought the Sabres the next year for $189 million and in 2014, outbid groups led by Donald Trump and Bon Jovi to pick up the Bills for $1.4bn.The Pegula family has a staggering worth of $11.8bn.Navarro, meanwhile, is the daughter of Ben Navarro, a former Citigroup banker who co-founded Sherman Financial Group in 1998.Since 2021, the Charleston-based billionaire has spent more than $350m buying up property around the South Carolina city, including a stadium and a historic hotel.Navarro has also spent over $300m to buy two professional tennis tournaments, in Cincinnati and Charleston. His Credit One company now sponsors both.The businessman is now worth $3.2bn.Pegula owns the Bills and the Sabres, and is worth a staggering $11.8bnGettyNavarro’s Capital One company sponsors two tennis tournamentsGettyJessica Pegula and Emma Navarro are ‘inspirational’ US Open playersWhile there won’t be billions at stake on the court this week, with the women’s US Open champion set to bank $5.5m come this weekend, bragging rights certainly will be when Pegula and Navarro meet in the last eight.Former US Open finalist, Greg Rusedski, praised both women for their impressive work ethic on the WTA Tour ahead of their meeting.“She’s a maximizer. She’s somebody who’s peaked later on,” Rusedski said of Pegula on his Off Court podcast.“She wasn’t one of these teenage stars who all of a sudden burst on the scene and everybody was talking about. So, every year she’s looking to get better.“But does she have enough firepower to win a major? That is the big question. Can she get to semis and finals of slams? Yes.“So, you know Pegula to me, I have nothing but respect… a person who just maximizes everything. So impressive, especially from her background.World No. 3 Pegula is favorite to win against Navarro at the US OpenGetty“I mean, her dad’s a billionaire, owns the Buffalo Bills, the Sabres, but yet she puts in the work, grinds, and is very inspirational.“With that sort of background, it’s very unusual to have someone this successful in tennis and in this sport.”Rusedski then extended the same respect to Navarro.He added: “Navarro is the same as well. Her father owns Capital One, who owns a tournament in Cincinnati.Navarro is working her way back to her best tennisGetty“She’s had some health issues and now she’s finally feeling good again. She was a top 10 player. She’s back knocking on the door. The all-American quarterfinals are guaranteed one in the semi-finals.”Pegula will be the heavy favorite heading into Tuesday’s battle of the billionaire heirs.She’s won all four of her career head-to-head meetings against Navarro, including their most recent clash in the round of 32 in Cincinnati last month.Pegula and Navarro are the first two Americans to meet in the women’s singles quarterfinal at the US Open since Serena Williams defeated sister Venus in 2015.Navarro and Pegula meet in the first all-American US Open QF since 2015Getty“Jess is really tough,” Navarro said, looking ahead to their next match.“She probably hits the flattest ball on tour, keeps it low, can hit it short and flat or deep and it looks the same. Just a really great ball striker and super consistent from the baseline.“I think I’ll have to match that and try to get her out of her rhythm a little bit.“I have lost to her a few times now, but there’s always that time when you get over the hump and get the win, so hopefully that will be in a couple of days.”