Oct 9 (Reuters) - The Chicago Sky takes on the red-hot Mercury in Phoenix to kick off the best-of-five WNBA Finals on Sunday, hoping to keep their Cinderella story on track to hoist the trophy for the first time. Chicago overcame seven straight losses earlier this year to end the regular season 16-16, before stunning the top-seeded Connecticut Sun in the semi-finals, and will need everything in its arsenal to avoid repeating history after the Mercury swept them in the 2014 Finals. "Our big focus this postseason ... has been about our defense, our rebounding, our ability to move and share the ball," two-time league MVP Candace Parker told reporters. "I think if we do that - it"ll still be hard - but I like our chances." Parker signed with her hometown team this year after 13 seasons with the Los Angeles Sparks, joining veteran point guard Courtney Vandersloot, who put up the league"s second-ever postseason triple-double last month and All-Star Kahleah Copper, who averaged 18.2 points per game in the playoffs. But to seize the WNBA crown, the Sky will have to take down titans including all-time scoring leader and 10-time All-Star Diana Taurasi, who put away 14 points in the fourth quarter of the Sky"s 87-84 win Friday over the Las Vegas Aces in Game 5 of the semi-finals. There is also the 6"9" impenetrable force of nature Brittney Griner, the best center in the league, who finished second in MVP votes this year behind Sun forward Jonquel Jones and put up 21 points and 9.7 rebounds per game in the playoffs. "She"s just been so incredible all year for us," three-time champion Taurasi said of Griner in a televised interview. "We"ve asked her to do everything: Play 40 minutes, defend the best player, help, block shots, score, rebound - she"s incredible." Taurasi already has plenty to celebrate after her wife, retired WNBA player Penny Taylor, gave birth to their second child on Saturday morning. The team will have to do without Canadian point guard Kia Nurse, who tore her ACL in Game 4 of the Mercury"s semi-final series against the Aces. The WNBA Finals kick off on Sunday.