Question: Clay Guida was the inaugural strikeforce lightweight champion, and holds a notable victory against a fighter who is currently ranked as #13 in what?
Context: Clayton "The Carpenter" Guida ( ; born December 8, 1981) is an American professional mixed martial artist, fighting in the UFC as a Featherweight.  A professional competitor since 2003, Guida has also formerly competed for Strikeforce, the WEC, King of the Cage, and Shooto.  Guida was the inaugural Strikeforce Lightweight Champion He holds notable victories over former UFC Lightweight Champions Rafael Dos Anjos and Anthony Pettis. Din Yero Thomas (born September 28, 1976) is a retired American mixed martial artist who was featured on The Ultimate Fighter 4: The Comeback.  In the Ultimate Fighting Championships, Thomas is a UFC 41 Lightweight Tournament Semifinalist.  He holds a Black belt in Brazilian Jiu-Jitsu under Ricardo Liborio and currently runs two successful Brazilian Jiu-Jitsu and MMA academies in Port St. Lucie, Florida.  Thomas holds notable victories of (UFC Lightweight Champion) Jens Pulver, (UFC Welterweight Champion) Matt Serra, and (Strikeforce Lightweight Champion) Clay Guida. Joshua Joseph Thomson (born September 21, 1978) is an American mixed martial artist who currently competes in Bellator MMA's lightweight division.  A professional competitor since 2001, Thomson has also competed in PRIDE, Strikeforce, UFC, the World Fighting Alliance, and appeared at Dynamite!!  2010.  Thomson is a former Strikeforce World Lightweight Champion and a former Strikeforce U.S. Lightweight Champion. Michael Chandler Jr. (born April 24, 1986) is an American mixed martial artist fighting in the lightweight division.  He is currently under contract with Bellator MMA where he is a former two-time Bellator Lightweight Champion.  He was also the winner of the .  Chandler is currently ranked as the #7 Lightweight in the world accrording to FightMatrix.com and is regarded as one of the top 20 greatest Lightweight fighters of all time.  He was the 2011 Breakthrough Fighter of the Year.  He holds notable victories over UFC Lightweight Champions Benson Henderson and Eddie Alvarez. Gilbert "El Niño" Melendez (born April 12, 1982) is an American mixed martial artist who has fought at Featherweight and currently fights at featherweight in the Ultimate Fighting Championship (UFC).  He is a two-time Strikeforce Lightweight Champion and a former WEC Lightweight Champion.  He also competed in PRIDE FC, Shooto and Rumble on the Rock. Anthony Paul Pettis (born January 27, 1987) is an American mixed martial artist currently competing as a Lightweight in the Ultimate Fighting Championship (UFC), where he is the former UFC Lightweight Champion.  Pettis was also the final WEC Lightweight Champion prior to the promotion being merged into the UFC.  At one point, he was ranked as a top-ten pound for pound fighter.  He is currently ranked #13 in the official UFC lightweight rankings. Kaoru "Caol" Uno (宇野薫 , Uno Kaoru ) (born May 8, 1975) is a Japanese mixed martial artist.  He is the Co-Champion of the UFC 41 Lightweight Tournament and a former Shooto Lightweight Champion.  As one of the early Ultimate Fighting Championship's elite Lightweight competitors, Uno competed for the UFC Lightweight Championship on two separate occasions.  Despite falling short in both championship bouts; losing a five-round decision against Jens Pulver at UFC 30, to determine the inaugural UFC Lightweight Champion as well as a draw against B.J. Penn at UFC 41 (in a bout which would have determined the new UFC Lightweight Champion and UFC 41 Lightweight Tournament Winner), Uno is acknowledged as a pioneer for his impact and influence during the early era of the UFC Lightweight Division. Yves Ed'duvill Edwards (born September 30, 1976) is a retired Bahamian mixed martial artist, who is perhaps best known for competing in the UFC's Lightweight division, fighting 21 times in the promotion.  A professional competitor since 1997, he has also formerly competed for PRIDE, the WEC, Strikeforce, Bellator, EliteXC, King of the Cage, BodogFIGHT, the MFC, and HDNet Fights.  He is known as the first person to ever knock out former Strikeforce Lightweight Champion Josh Thomson. Samy Schiavo (born December 24, 1975 in Avignon) is a retired French mixed martial artist and taekwondo fighter.  Schiavo has previously fought in Cage Rage and the UFC.  Schiavo signed with the UFC early in 2008 and made his debut at UFN 13 losing to Clay Guida by TKO late in round 1.  Schiavo fought for the second time in the octagon at UFC 89 in Birmingham, England against Per Eklund.  Despite winning the first two rounds thanks to his stand up, Schiavo lost the fight by submission after he tapped out to a rear-naked choke in round 3.  Following the loss he was released by the UFC. Jason Guida (born August 4, 1977) is an American professional mixed martial artist currently competing in the Heavyweight division.  A professional competitor since 2003, he has fought for ShoXC, the WEC, Bellator, KSW, Adrenaline MMA, and World Extreme Fighting.  Jason is the older brother of Ultimate Fighting Championship veteran Clay Guida.
Answer: the official UFC lightweight rankings