SEATTLE -- The Storm needed a huge halftime rally to clinch the top seed in the Western Conference.
Lauren Jackson scored a season high 33 points to help Seattle rally from an 18-point halftime deficit to beat the Phoenix Mercury 91-85 on Tuesday night.
"That's what we've been talking about year long," said Sue Bird, who had 16 points. "We basically have seen every kind of game. We've been up, we've been down. We've had to come back."
Tanisha Wright added 14 for Seattle, which won its 12th consecutive game. The Storm are 12-0 at home and 16-0 in conference play.
Seattle coach Brian Agler stayed calm at halftime and reminded his team to simply pick away at the 18-point deficit.
"Twenty minutes is a long time and Brian talked about cutting it to 10 before the fourth quarter and we were down two," Bird said. "Sometimes you just have to look at it in little increments and chip away, chip away and it worked in our favor."
Diana Taurasi scored 27 and DeWanna Bonner 19 to lead Phoenix (10-13), which had won three in a row. The second-place Mercury dropped 11 games behind the Storm.
The Storm rallied from an 18-point halftime deficit to lead 65-64 early in the fourth quarter after Wright scored on a three-point play.
"You have to play 40 minutes to beat any team in this league," Taurasi said. "We put in a good first half and in the second half we didn't get some things we wanted to."
The Mercury briefly regained the lead before 3-pointers by Wright and Jackson helped give the Storm a 77-68 lead with 5:18 left and cap a 33-7 run from midway through the third quarter.
"They're a great team, no doubt about it," Jackson said of Phoenix. "To win tonight and get home court advantage during the playoffs is huge, especially against that team because you know not for one minute did they want us to win that game."
Taurasi scored 16, Bonner 12 and Temeka Johnson 11 to help the Mercury to a 56-38 halftime lead.
Houston opened the 1998 season with a 25-2 record.
Jackson had nine points and Wright six in the third quarter as the Storm cut an 18-point deficit to 64-62.
Seattle used an 18-3 run over the final 6:49 of the third quarter to get back in the game. The Storm shot 8 of 12 from the field. The Mercury shot 2 of 22.
Taurasi scored 11 in the first quarter to help give the Mercury a 25-20 lead. Bonner had 10 in the second quarter to boost the lead to as many as 18 points.
Phoenix shot 23 of 38 (60.5 percent) in the first half. The Storm shot 14 of 38 (36.8 percent).
Seattle's last loss was 72-65 at Indiana June 17. The Storm also lost 84-75 at Chicago May 27.
The Storm also won the three previous games this season against Phoenix, including 111-107 in triple overtime two weeks ago and 97-74 in Seattle June 6.
"We'll be all right," Phoenix coach Corey Gaines said. "I'm not disappointed at all. We lost to a good team, the best team in the league. We played them tough."