What should we expect from Dream, Mercury, Mystics and Storm in the WNBA semifinals?

Former UConn legends Sue Bird of Seattle and Diana Taurasi of Phoenix are on opposite sides in the semis. The Storm went 2-1 against the Mercury this season. Barry Gossage/NBAE via Getty Images

One WNBA semifinal pits two teams, top-seeded Seattle and No. 5 Phoenix, that have won five league titles between them. The other semifinal, between No. 2 Atlanta and No. 3 Washington, is a meeting of teams that have never won a championship. The Mystics, in fact, have never made it to the WNBA Finals. The Dream have reached the championship series three times, but they're 0-9 in those games.

The current playoff format, which was implemented in 2016, essentially did away with conference affiliation. Since then, the top eight overall teams in the standings make the postseason and then are seeded according to record through each round. Yet that didn't prevent traditional East versus West in the WNBA Finals, and that's what we'll get now.

Still, the perceived favorite, looking historically, is the winner of the Storm-Mercury semifinal. West teams have won 16 of the 21 WNBA titles. It would be 17, except Houston was in the Eastern Conference for the league's first season in 1997. But this could be the year a different team from the East joins the list of champions.

That's the quick overview as we head into Sunday's semifinal openers, with the Mystics and Dream in Atlanta (ESPN2, 3 p.m. ET), and the Storm and Mercury in Seattle (ESPN2, 5 p.m. ET). Here's a closer look at both playoff series.

Storm vs. Mercury: So we meet again

This marks the fifth time they've faced off in the postseason. In 2007, when Phoenix won its first title, it beat Seattle in the conference semifinals. In 2010, the eventual champion Storm defeated the Mercury in the conference finals. In 2011, the Mercury won in the conference semis. Then last year, Phoenix won the first-round game against visiting Seattle.

This year, the teams met twice in the season's first week in May, with each winning on the other's home court. Seattle won at Phoenix on July 31 in their third regular-season meeting this year.

At 26-8, the Storm had their second-best record in franchise history, behind the 28-6 of their 2010 championship team. That year was also the last time Seattle won a playoff series. The Storm lost in the conference semifinals from 2011-13, didn't make the playoffs in 2014 and '15, and lost in the first round the last two years.

"They had already gone through some growing pains, and they were in a position to find out who they were," coach Dan Hughes said of taking over at a fortuitous time in 2017. "It's really been fun for me to jump back to where a team is in that position for that next step. You feel really energized when you've got players at that stage."

Hughes took San Antonio to the 2008 WNBA Finals behind point guard Becky Hammon, and now has a team guided by Sue Bird, who will turn 38 in October, yet still was second in the league in assists this season at 7.1 per game.

"They are not only good players on the court, they are teachers on the court," Hughes said of Bird and Hammon, who retired in 2014 and is now an NBA assistant at San Antonio. "I've always believed in letting the point guard sync the game, and those two are amazing. Their IQ, their understanding of what we're trying to do, is just unmatched.

"There are times with Becky and Sue, where they do things with the team, and it's almost like they have mental telepathy right to four other people."

Bird -- one of five former No. 1 draft picks in this series, along with Seattle's Jewell Loyd and Breanna Stewart and Phoenix's Diana Taurasi and Brittney Griner -- has been the constant for the Storm since 2002, save when she sat out the 2013 season resting and recovering from surgery. This year she has plenty of talent around her, starting with Stewart, who averaged 21.8 points and 8.4 rebounds while playing with the most efficiency of her young pro career. Loyd averaged 15.5 points and was a particular thorn for the Mercury during the regular season, scoring 29 points in both the victories over Phoenix.

Forward Natasha Howard, obtained via trade with Minnesota, has been even better than Hughes expected -- and he was expecting a lot. Howard and Alysha Clark form the backbone of Seattle's defense. Hughes particularly praises how Clark has completely remade herself as a player in the pros, going from a high-volume scorer in college to a lockdown defender as a pro.

As for the Mercury, they had the ups and downs this season that Seattle didn't, yet here they are in the semifinals again. Phoenix is trying to avoid its fate of the past two years, when the Mercury won two games to get to the semis but were swept once they were there.

From July 8 to Aug. 7, Phoenix went 2-11 and couldn't seem to build any momentum, despite having three All-Stars in Taurasi, Griner and DeWanna Bonner. The Mercury lost forward Sancho Lyttle to an ACL injury June 30, and her absence was part of the problem.

Moving Bonner to power forward in August helped the turnaround. So did Phoenix closing with a stretch of several home games. The second-round victory at Connecticut on Thursday was the first time since July 15 the Mercury had to play outside the Pacific time zone (Arizona is Mountain time but doesn't observe daylight saving); they've been on a stretch of playing at home or at Las Vegas or at Los Angeles.

So even with going from Connecticut to Seattle now, the Mercury should be relatively rested. They looked strong in controlling the first-round game against Dallas, 101-83, and then went on a late surge to beat the Sun 96-86. In those two games, Taurasi, Bonner and Griner combined to score 149 points. Their 77 combined points in the second round were the most by any teammate trio in a playoff game in WNBA history, per Elias Sports Bureau.

Phoenix's Sandy Brondello is a former WNBA player and the only one among the four semifinalists who has coached a team to a WNBA title, leading the Mercury to the 2014 crown. Hughes retired in 2016, but returned this year to coach his 17th WNBA season.

Dream vs. Mystics: Maximizing potential

Atlanta won the season series 2-1, with all the games in July. These teams were battling until the end for No. 2 in the standings and the bye into the semifinals. The Dream got it despite losing Angel McCoughtry, who has been the face of the franchise since 2009, to an ACL injury on Aug. 7.

But if there were ever a Dream squad capable of contending for a title even without McCoughtry, it's this one. Nicki Collen sought to both build up McCoughtry's spirits in dealing with the injury and also convince her team it could be successful anyway.

Acquiring Renee Montgomery and Jessica Breland via free agency in the offseason has been huge for the Dream.

"When I got the job and asked the players what we needed, they talked a lot about the point guard spot," Collen said. "I thought Renee was a good fit, but I didn't know just what I was getting until training camp. We've built a relationship. ... She came in and won the starting job and won over her teammates. She doesn't complain about bumps and bruises or anything; she just wants to play."

Breland's even-keel personality matches that of fellow post player Elizabeth Williams, but that shouldn't be mistaken for any lack of intensity. They both are particularly key to Atlanta's defense, which had the lowest opponent scoring average (79.5 PPG) of any of the teams still in the playoffs.

The Dream traded for guard Alex Bentley on July 9, and they've benefited from her scoring threat and ability to push the pace.

Then there's guard Tiffany Hayes, an All-Star last year who should have been one this year. She leads the Dream in scoring (17.2 PPG) and has the kind of fiery demeanor that Collen loves.

"I think all season, she has stayed with a different level of composure," Collen said. "She's still an emotional kid and she wears those emotions on her sleeve. But she doesn't take plays off. She may get frustrated at one end, but then channels that amazingly well.

"What we've challenged Tiffany to do is share the ball more. She's so electric, and so slippery in trying to find the little seams in the defense. But I tell her, 'OK, you are probably better than anybody in our league at getting through a tight space and scoring. But think about if that space is that tight, that means somebody else might be really open.'"

Collen expected Atlanta's defensive success, but in Washington, defense isn't what you typically think of first -- or at least it wasn't when the season started. The Mystics have come together defensively really well, led by veterans Natasha Cloud and LaToya Sanders and rookie Ariel Atkins, the youngest player in the semifinals at 22.

Those three also have contributed on the offensive end to back up Elena Delle Donne (20.7 PPG) and Kristi Toliver (13.9), who both can be lethal scoring weapons. The Mystics' 96-64 dismantling of Los Angeles in the second round exposed the Sparks' fatigue from end-of-season travel and illness. But the Mystics played so well, it's hard to say even a fully rested Sparks team could have defeated them.

Over the years, Washington has been both a snakebitten franchise and one that has inflicted its own injuries with questionable organizational decisions. That changed when Mike Thibault took over as head coach for 2013; the Mystics have made the playoffs every year but one under him. They made the semifinals last year, but were swept by the eventual champion Lynx.

Washington would have loved to have forward Emma Meesseman this summer, but she was committed to staying with the Belgian national team and preparing for the FIBA World Cup. It would be great to see what she'd add to this team. But the fact is, the Mystics haven't made any excuses.

They have won nine of their last 10. Other than a loss in the regular-season finale at Minnesota when they rested their starters in the second half of what was then a meaningless game, the Mystics are unbeaten since the All-Star break.

Atlanta is 7-2 in that same stretch, so this is a meeting of two teams playing well at the right time.