Nassourdine Imavov has burrowed into the Ultimate Fighting Championship middleweight division’s Top 15 rankings. Now, he must prove he has staying power.

The Russian-born Frenchman will ride a three-fight winning streak into his showdown with Kelvin Gastelum in the UFC Fight Night 217 headliner on Saturday at the UFC Apex in Las Vegas. Imavov carries a 4-1 record through five assignments inside the Octagon. He last appeared at UFC Fight Night 209, where he took a unanimous decision from Joaquin Buckley in their three-round pairing on Sept. 3. Gastelum, meanwhile, has lost five of his past six bouts, including two in a row. “The Ultimate Fighter” Season 17 winner last competed on Aug. 21, when he dropped a unanimous decision to Jared Cannonier in the UFC on ESPN 29 main event.

As Imavov and Gastelum draw ever closer to their forthcoming battle at 185 pounds, a look at some of the numbers that have accompanied them to this point:

27: Years of age for Imavov, who was born on March 1, 1995 in Makhachkala, Russia.

4: Imavov victories by submission, accounting for 33% of his career total (12). His methods of choice: two rear-naked chokes, one brabo choke and one kimura. Imavov holds five other victories by knockout or technical knockout (42%) and three more by decision (25%).

122: Seconds needed for Imavov to put away Gary Formosa with punches at a Centurion Fight Championship show on Nov. 4, 2017. More than five years later, it remains his fastest finish to date.

8: Countries in which Imavov has competed as a mixed martial artist. He has gone 3-1 in France, 2-1 in the United States, 2-0 in Malta, 1-1 in Poland, 1-0 in Switzerland, 1-0 in Italy, 1-0 in Senegal and 1-0 in the United Arab Emirates.

.711: Cumulative winning percentage between the three men—Majdeddine Ayadi, Michal Michalski and Phil Hawes—who have beaten Imavov. They boast a combined record of 32-13.

31: Years of age for Gastelum, who was born on Oct. 24, 1991 in San Jose, California.

6: Gastelum wins by knockout or technical knockout, accounting for 37.5% of his career total (16). His list of UFC victims: Michael Bisping, Tim Kennedy and Nate Marquardt. Gastelum owns four other wins by submission (25%) and six more by decision (37.5%).

350,000: Dollars in post-fight bonuses banked by Gastelum across his 20 appearances in the UFC. He has been awarded “Fight of the Night” on four occasions and “Performance of the Night” three times.

124: Significant strikes landed by Gastelum in a unanimous decision over former welterweight champion Johny Hendricks at UFC 200 in 2016. It established a personal high-water mark for the Rafael Cordeiro protégé that still stands.

165: Combined victories between the eight men—Cannonier, Robert Whittaker, Jack Hermansson, Darren Till, Israel Adesanya, Chris Weidman, Neil Magny and Tyron Woodley—who have defeated Gastelum. They sport a cumulative .764 winning percentage at 165-49-2.