Manny Pacquiao says next month’s clash with Errol Spence Jr could be the most difficult of his celebrated career, as the Filipino got down to work with his US training camp. The eight-division world champion, now 42, returns to the ring for the first time in more than two years against the undefeated WBC and IBF welterweight champion in Las Vegas on August 21. Pacquiao has not fought since his split-decision victory <a href="https://www.thenationalnews.com/sport/other-sport/manny-pacquiao-proves-age-is-just-a-number-after-stunning-win-over-keith-thurman-1.888758" target="_blank">against the previously unbeaten Keith Thurman</a> in July 2019. The future Hall of Famer arrived in Los Angeles earlier this week, before taking part in his first training session with long-time coach Freddie Roach on Monday. Pacquiao, a sitting senator in the Philippines, said via a news release: “Errol Spence is a very difficult fight for me, perhaps the most difficult of my career. But I have been an underdog my whole life. I am used to that. It is why I work so hard. “But the love and the prayers of my fellow Philippine citizens and Filipinos around the world sustain and inspire me. I fight for the glory of my nation and for underdogs everywhere.” Pacquiao, who earlier this year was stripped of his WBA (super) welterweight belt because of inactivity, will be training once more at Roach’s Wild Card Boxing Club in Hollywood, California. The <a href="https://www.thenationalnews.com/sport/other-sport/manny-pacquiao-s-comeback-fight-against-errol-spence-confirmed-for-august-21-1.1248515" target="_blank">bout against Spence</a>, 31, takes place at T-Mobile Arena. Pacquiao’s record stands at 62-7-2 (39 KOs), while Spence boasts a 27-0, with 21 KOs. The American is viewed as a heavy favourite for the encounter. Roach, however, was suitably impressed with his star pupil following their first session back together. According to the release, Pacquiao was kept late for his afternoon pad work at Wild Card because of a random drug test from VADA (Voluntary Anti-Doping Association) at his house. Still, Roach said following their three-hour workout: “If this is how Manny hits with jet lag, I may need to get new gloves with thicker padding for our next sessions. He was incredibly sharp for his first day. He hit hard with good power. "After all these years, I’m still amazed at the great condition he’s in when he comes to training camp. After traveling around the world yesterday, he put in a full day here: mitts, speed bag, shadow boxing, the works. The best part was at the end when he lifted his shirt to show me his six pack and said, ‘Freddie, I’m still here.’”