The Shock (6-1) won the second of their last 22 meetings with Minnesota (5-2) and extended their winning streak to six — a franchise best since 2010. Tulsa also avenged its lone defeat of the season, an 83-75 loss to the Lynx in the season opener for both teams on June 5.
Diggins kept the Shock close with 10 points in the latter part of the third quarter, and Jordan Hooper's 3-pointer with 2.9 seconds left gave the Shock a 58-57 lead going into the fourth.
Tulsa stretched it to 71-63 before Minnesota rallied within three with 1:50 left. Riquna Williams and Diggins then hit back-to-back 3s to put it out of reach at 82-73.
The Shock struggled early, making just two of their first 10 field goal attempts and 6 of 21 in the first quarter. Williams credited their confident mentality for the turnaround.
"Keep shooting" Williams said. "We don't know the numbers but we keep shooting. Eventually one of us will get hot and it will trigger down the line."
Williams finished with 17 points and Courtney Paris added 16 points and 11 rebounds for the Shock.
Rebekkah Brunson led the Lynx with 18 points, Maya Moore scored 16, and Seimone Augustus and Damiris Dantas added 15 apiece.
"Obviously Tulsa is excited to play and wanted to win," said Minnesota coach Cheryl Reeve. "They did what they needed to do, they played great. I thought Diggins played great, Riquna Williams has a nice bounce in her step. Courtney Paris gave them great stuff. I give them credit."
The Lynx opened the game on a 9-0 run as the Shock struggled early. Moore had nine points in the first quarter and the Lynx had their largest lead of the game at 23-13 just before the end of the period.
Tulsa took its first lead of the night at 34-33 with 2 minutes left in the half when Williams capped a 12-2 run with a 3-pointer.
Neither team was able to break apart in the third until Minnesota had a 5-0 run to lead 57-52 with 1:31 left. But Diggins and Hooper's back-to-back 3s to end the quarter gave Tulsa the lead for good.
"That was disappointing," Moore said. "We worked so hard to get our lead back and not defending the 3-point line is one way to lose momentum very quickly."
Shock head coach Fred Williams credited the victory to his team's resilience.
"The real power of this team is to play being down really early and to sustain a lead toward the end," Williams said. "Wow, these ladies just really played hard and played incredible today."
Diggins finished 3 of 4 from 3-point range and handed out eight assists. Paris reached a double-double when she scored the first points of the second half.