Sydney, Jan 2 : Tomas Barrios Vera and Daniela Seguel defeated Top-10 stars Maria Sakkari and Stefanos Tsitsipas 6-7(5), 6-3, 10-6 as Chile pulled off a stunning 2-1 upset of Greece in a Group B encounter at the United Cup on Tuesday. The all-important victory in the mixed doubles means the South American country is now 1-1 in Group B. Earlier in the day, Sakkari gave Greece a quick lead before Nicolas Jarry survived a stern test from World No. 416 Stefanos Sakellaridis to level the tie and force a deciding mixed doubles. After letting slip a 5/1 advantage in the first-set tie-break, the Chileans did not make the same mistake again. Jarry sent the tie to a decider when he overcame the inspired effort of Sakellaridis 6-3, 3-6, 7-5 after two hours and 22 minutes. Sakellaridis replaced World No. 6 Tsitsipas in the men's singles clash. All six Sydney ties this year have gone to a deciding mixed doubles match. Sakellaridis earned United Cup experience last year when he went 1-2, including a win over Belgian Zizou Bergs. Against Jarry, the No. 19 in the Pepperstone ATP Rankings, the Greek played the match of his life. The 19-year-old showed great courage inside a packed Ken Rosewall Arena, saving 10 of the 12 break points he faced. His competitive spirit fired up the Greek fans and his team, including Apostolos Tsitsipas, the father of Stefanos Tsitsipas and playing captain Petros Tsitsipas. Jarry won 85 per cent of his service points, which ultimately kept Sakellaridis at bay. The Chilean's net-rushing strategy of the first two sets proved successful, but he ultimately triumphed by relying on his serve and outlasting his opponent from the baseline. Sakkari earned a commanding victory for Greece in the country's opening match of the 2024 United Cup, defeating Chile's Daniela Seguel 6-0, 6-1 at the mixed-teams event on Tuesday in Sydney. In her first match of the season, World No. 8 Sakkari, the highest-ranked Greek woman in history, took just 68 minutes to ease past Seguel, a former Top 200 player currently ranked No.671. After clinching the Greeks' first point in Group B, the 28-year-old Sakkari is now 4-1 in United Cup singles matches in her career. She won all three of her group-play matches last year during Greece's run to the semi-finals. In the first set, Sakkari demonstrated the variety of skills that have led her to a year-end Top 10 ranking in each of the past three seasons. Sakkari out-rallied Seguel in a love break for 2-0, then powered to the double-break advantage by cranking a stunning return winner to reach 4-0. Sakkari closed out the opener with another love break, as she finished the first set three-for-three on break points while never facing a break point on her own serve. Seguel won only one of her 11 first-serve points in the opener. Seguel, who was facing a Top 20 player for the first time in her career at the age of 31, was able to get on the scoreboard with a gritty hold for 1-1 in the second set. But the Chilean saw a 40/0 lead slip away as Sakkari broke serve in a gruelling game for a 3-1 lead. Sakkari did not face a break point until the very last game of the match. The Greek successfully erased that chance, and she prevailed in a lengthy rally on her second match point to close out the routine win. /IANS