But that was 2013. Friday, the duo tangled again, and the end result was an early candidate for 2014's Fight of the Year.
In a finish which will be long remembered, Curran, likely needing a stoppage to win the fight, got Straus to tap with 14 seconds left in the final round. Curran regained the championship in the main event of Bellator 112 at the Horseshoe Casino just outside Chicago.
"All I can say is I've got mad respect for Daniel Straus," said Curran (20-6).
Curran came out strong in round one, with sharp striking, and largely getting the better of things both from distance and in the clinch. Straus went for a late submission, but it wasn't enough to take the round.
Straus (22-5) turned it on in round two, busting Curran open with a sharp left to Curran's right eye. While Curran landed solid counters, Straus landed clean and often with his boxing.
Round three was the bout's closest, one that could have been scored either way, as Curran came out flying, but Straus finished the round stronger.
By round four, both fighters tired. But while it took Straus two attempts to make weight on Thursday, he was the one who initiated more action and landed more often.
The final round was briefly halted to wipe excess vasoline off the cut over Curran's right eye. Straus appeared to be controlling the round until the final 90 seconds, in which Curran got Straus to the mat and got in his rear-naked choke.
In a dramatic final minute, Straus gave the thumbs up sign more than once, but when Curran kept the choke tight, Straus tapped just 14 seconds before he could have very well taken home a decision win.
"I knew it was close but I think Daniel was ahead in the round, I knew I had to get a finish," Curran said.
With that, Curran took a 2-1 lead in his series with Straus. Curran knocked out Straus in a 2009 XFO fight in Illinois, before Straus won the rematch in November.
Curran was granted an immediate rematch against Straus following Straus' victory. At the postfight news conference, Bellator CEO Bjorn Rebney indicated Curran would next meet tournament winner Patricio Freire, with Straus meeting the victor.
"Man, I can't even explain, a lot of blood sweat and tears go into this," Curran said. "This is my passion, I just want to relax and enjoy this awhile.
Judges' scores going into the fifth round were all over the map, with one judge having three rounds to one for Curran; another 3-1 for Straus; and the other tied at two.
The remainder of the main card were first-round bouts in the Bellator Season 10 welterweight tournament. Season 7 tourney champ Andrey Koreshkov (15-1) stands two wins away from another tourney victory, as he left no doubt about it with a swift finish of UFC and Strikeforce veteran Nah Shon Burrell (11-4)
Koreshkov, whose only career loss was a title challenge to former champ Ben Askren, drilled Burrell with a vicious body kick square on the ribs. Burrell dropped, then Koreshkov landed a bunch of right hands before the bout was stopped just 41 seconds in.
The Omsk, Russia native now has 12 finishes in his 15 wins.
"Tonight we showed the results of my work," Koreshkov said through an interpreter. "Don't underestimate Russian fighters."
Sam Oropeza put his stamp on the tournament with a gigantic right hand. That right landed on the jaw of previously undefeated Brazilian Cristiano Souza (7-1) and put Oropeza into the tourney semifinals. The stoppage came at 3:07 of round one.
After a round mostly marked by clinch work along the fence, Oropeza created distance and landed his big right. A handful of lefts to the downed American Top Team Fighter hastened the stoppage, as Oropeza scored his sixth career KO/TKO.
"Christiano is a warrior, but I felt his power and I knew he wouldn't be able to take me out," said the Philadelphia-based Oropeza (11-2). "I was sending a message to everyone in that tournament field."
Oropeza will face Koreshkov in the semifinals.
Juarez (21-9) got off to a fast start and got McDonough into a deep arm triangle choke. While it looked for awhile like McDonough might go out, he managed to survive. He then dominated the next two rounds with takedowns and ground-and-pound. The 28-year old St. Cloud, Minn. native advanced to the tourney semis with across the board, 29-28 scores.
The top undercard bout was the other first-round welterweight tournament fight. Nathan Coy punched his ticket to the semifinals with a unanimous-decision win over veteran Paul Bradley, taking across-the-board 30-27 scores. McDonough will meet Coy in the other tourney semi.