The final leg of John Cena's Farewell Tour is heating up. The Franchise Player is set to face his longtime rival, Brock Lesnar, in a singles match at the upcoming Wrestlepalooza Premium Live Event on September 20. In an interesting possibility, two-time World Heavyweight Champion Gunther could assist The Never Seen 17 in defeating The Beast Incarnate.Lesnar made his earth-shattering return to WWE in the closing moments of SummerSlam Night Two, laying out John Cena, who had lost the Undisputed WWE Championship to Cody Rhodes in a Street Fight. The Beast Incarnate then went on another short hiatus before making his presence felt once again on last week's SmackDown, interrupting the Intercontinental Championship match between Cena and Sami Zayn.That said, the highly anticipated bout between John Cena and Brock Lesnar may end on a controversial note, as Gunther could make his return and cost The Beast Incarnate the match. The Ring General has been sidelined with a nose injury since losing the World Heavyweight Championship to CM Punk at The Biggest Party of the Summer.While the former Imperium leader is a well-known prizefighter, the World Heavyweight Title is currently intertwined in the ever-growing rivalry between Seth Rollins and The Second City Saint, which now involves their spouses as well. Including The Ring General in the title picture may not be a wise move at this time.Therefore, a potential rivalry with The Beast Incarnate would be the perfect way to reintroduce the 38-year-old to the mix. Gunther has previously expressed interest in facing Lesnar, referring to the veteran as his "end boss." The two had a brief yet intense interaction during the 2023 Men's Royal Rumble Match, which evoked a loud reaction from the crowd.The Triple H-led creative team could plant the seeds for a one-on-one showdown between Gunther and Brock Lesnar at Wrestlepalooza. That said, this is just speculation for now.Gunther is rumored to be John Cena's final opponentJohn Cena will hang up his wrestling boots in December this year. During his year-long Farewell Tour, Cena has faced off against several major stars, including Cody Rhodes, Randy Orton, and CM Punk. With a handful of appearances left before his retirement, fans are wondering who will be Cena's final opponent.Interestingly, according to a report from WRKD Wrestling, Gunther is slated to face the 17-time World Champion in his last match. The Ring General retired the legendary Goldberg at Saturday Night's Main Event XL in July. Now, a potential bout against John Cena in what could be his final in-ring outing would not only be exciting for fans but also elevate Gunther to a new level.That said, nothing has been confirmed as of now. Fans will have to wait and see what the Triple H-led creative team has planned for the remainder of Cena's Farewell Tour.