The Shock (11-21) took down the Silver Stars, 98-65, and one player accounted for more than half the team’s points.
Williams shot more than 60 percent from the field including an 8-of-14 performance from behind the arc.
““Honestly, I just went into a zone,” Williams said. “Normally when I’m like that, 51 points won’t happen, but I do pretty good.
“Tonight, I’m not really sure what happened honestly. I just went out, had fun and didn’t think. The shot was there, the basket was there, the and-one was there, and we were playing for pride. We can’t make the playoffs, so it’s all pride at this point.”
The previous record of 47 points was held by Phoenix’s Diana Taurasi and Seattle’s Lauren Jackson, a couple of the league’s big names.
“It’s amazing,” Williams said. “I’m still speechless. It feels great, and I’m only in my second year in the league.
“To capture that at such a young age as such a young player is amazing. I shot it pretty well. It wasn’t a bad shooting night. To do that was amazing.”
Tulsa trailed by four at halftime, but Williams came alive in the second half with 35 points.
“We came out of that second half with a lot of energy,” said Shock coach Gary Kloppenburg. “I thought we really showed up on defense in that third quarter and then we just got going offensively. Any time you get a player like Williams going, we started to ride her as she stayed hot the whole way.”
Williams had an 11-point run by herself in the third quarter to put her team on top for good.
And as the game wound down with the Shock clearly pulling away, even the San Antonio crowd got into it as Williams neared the scoring mark, cheering her on.
““Amazing. I kind of got a little teary,” Williams said. “I also took a hit so it was a combination and I was able to hide it a little. It’s great. I’m a small town kid. It’s my dream come true. I never thought I would be at this point.”
Shock rookie Skylar Diggins also had an impressive night with one of her stronger scoring performances, putting in 20 for Tulsa.
The Shock have three games remaining in 2013. They face Seattle in back-to-back contests, with the first being the home finale at the BOK Center on Thursday at 7 p.m.