PHOENIX (AP) — The Phoenix Mercury got off to good starts against the Seattle Storm in the first two games of the WNBA semifinals. They've been good in the fourth quarter, too, highlighted by Diana Taurasi's clutch shots at the end of regulation in Game 2.

Now if the Mercury could just get those two middle quarters right.

Phoenix lost both games in Seattle despite massive comebacks, a product of its struggles in the second and third quarters. The Mercury will need to play better in the middle two quarters in Game 3 on Friday or their bid to reach the WNBA finals for the first time since 2014 will come to an abrupt end.

"The second and third quarters have been our Achilles' heel, the first and fourth quarters have been their Achilles' heel," Taurasi said Thursday. "It's just a matter of doing the little things. Turnovers have been a big part of when they've gone on those runs and we need to do a better job of getting better shots and back in transition."

Phoenix struggled after a good start in Game 1 Sunday in Seattle, falling into a 16-point second-half hole before rallying within two with a minute left. League MVP Breanna Stewart put an end to the Mercury's run with a big basket and the Storm pulled out a 91-87 victory.

Game 2 had a similar plot line: Both teams played well early, Seattle pushed the lead to 17 points and the Mercury closed with a big rally at the end of regulation. Taurasi, the WNBA's all-time leading scorer, provided the heroics, hitting three 3-pointers in the final 1:36, including an off-balance shot with 3.7 seconds left to send the game to overtime. The Storm took over in the extra period and again won 91-87 to take a 2-0 lead.

Now the series shifts to Phoenix, where the Mercury will try to prevent the Storm from reaching the WNBA finals for the first time since winning their second title in 2010.

"We've had difficulty stopping them from making those runs, but at the same time we've been able to answer," Storm coach Dan Hughes said. "It's a little bit of good and bad."

The key to the Storm's runs has been their ability to turn bad shots and turnovers by Phoenix into transition points. Seattle was the WNBA's best fast-break team and near the top in offensive efficiency, its roster filled with multi-dimensional players who can score on the break.

Seattle stormed the Mercury with a series of fast-break layups created off turnovers during its big runs in the first two games of the semifinals, putting Phoenix in big holes.

The Mercury rebounded in both games by taking care of the ball better and making more shots, forcing Seattle into more of a half-court game. Doing that for four quarters, not just two, will go a long way in determining whether Phoenix forces a Game 4 on Sunday or sees its season end.

"That's something we're definitely looking to do, push the pace," Stewart said. "We want to push the pace, get out in transition because we know it's hard for teams to match up with us.

Even if the Mercury are able to slow the Storm, they still have another problem: Finding a way to stop Stewart.

The No. 1 overall pick in the 2016 WNBA draft, she won her first league MVP trophy this season after averaging 21.8 points and 8.4 rebounds while shooting 53 percent, including 41 percent from 3-point range.

Stewart has been nearly unstoppable against the Mercury, scoring 27 points in Game 1 and 28 in Game 2 while hitting a combined 19 of 39 shots.

Now she has the Storm on the cusp of a WNBA finals appearance.

"We've got to play tougher," Mercury coach Sandy Brondello said. "We have to know where she is, we have to find her in transition. She's a great player and it's not going to take one player. It's going to take everyone being locked in and knowing where she is at all times."