Williams and Tunisia's Jabeur defeated Shuko Aoyama and Chan Hao-ching 6-2, 6-4 in the quarter-finals of the Wimbledon warm-up event at Devonshire Park.
The doubles team made it two from two with Williams able to fire a warning to her rivals with flashes of brilliance. The American great produced several aces and winners, especially at the net, despite shadows gathering at Devonshire Park to show the 23-time Grand Slam champion may just be a contender at SW19 next week.
Williams is playing her first tournament since she made a tearful, injury-enforced exit from Wimbledon last year.
It took only two minutes for the American to send down an ace before several clinical volleys provided the first break. The opening set was wrapped up in 25 minutes and another break inspired by Williams in the ninth game of the second set put them on the brink of victory.
"I don't know if you know the team name? It's 'OnSerena'!" Williams said of her partnership with Jabeur, who had never played with the American until this week.
"I have had some really good training leading up to Wimbledon and up to this tournament, really hitting the ball well. I feel like I have been serving well so that's been really good.
"It was actually good match play and match practice, which is exactly what I needed. I couldn't have asked for more."
Williams had admitted on Tuesday that she had doubts if she would ever make it back after her injury lay-off, but has found form at just the right time with Wimbledon on the horizon.
"I will always enjoy the competitive side. There is a part of me that will always miss it, no matter what happens," she said.
"I was just recovering and taking time off, just taking mental breaks. Now when I'm back, it's like, especially this match in particular, OK, you really remember the competitiveness."
After missing the deadline to enter Wimbledon, 'OnSerena' will not grace the All England Club as a pair next week but more events could be on the horizon with their semi-final tie set for Friday.
Jabeur insisted: "We played much better. I think we are getting used to each other now. I am ready for more tournaments to be honest with you."