Having been appointed a flight techniques inspector of the 324th Fighter Aviation Division in March 1950, he was deployed to China in December that year with the rest of the division. However, he was given command of the 176th Guards Fighter Aviation Regiment in April 1951 after issues came up with the regiment's commander at the time resulting in Ivan Kozhedub deciding to seek out a more experienced leader for the regiment and eventually choosing Vishnyakov. Later that month on 24 April he made his first combat sortie in the war, during which the MiGs he was flying with encountered a group of eight F-86s. During the ensuing dogfight, captain Vasily Murashev of the third squadron was shot down by William Hoyd while attacking the two F-86 on Vishnyakov's tail, and although he survived by bailing out of his crippled plane via his parachute, his injuries rendered him unable to continue flying in the war. Eventually on 20 June Vishnyakov himself gained his first aerial victory over Korea, shooting down a piston-engined US aircraft over Simbi-do island at an altitude of approximately 2000 meters. Later on in the war on 8 June over Sensen, Vishnyakov took credit for his first jet shootdown after leading a group of 20 MiGs in a dogfight against 24 F-86; however, because he fired at the enemy aircraft from a significant distance during the battle and US records do not indicate any jets were written off that day combined with the high rate of overclaiming in the Korean War, the most plausible explanation is that Vishnyakov simply damaged an F-86 instead of gaining a true shootdown on that day. However, in December that year, he went on to gain several credited aerial victories in a short period of time. On 1 December he led a group of 20 crews from his regiment to a spot where enemy aircraft were expected to arrive: there, at an altitude of 7,500 meters, they came across 16 Australian Gloster Meteors, which were fairly vulnerable to the MiGs. Vishnyakov ordered ten of the MiGs under his command to stay above them as cover, while he led the remaining crews in an attack on the Gloster Meteors. In the ensuing combat, the Soviet pilots claimed nine shootdowns without suffering any losses, including one attributed to Vishnyakov. However, Australian reports paint a very different picture of the encounter, claiming to have shot down a MiG and lost in that lost only three, not nine aircraft in the battle. Argentine aviation historian Diego Zampini counts five Australian losses since an additional two Australian aircraft were written off after returning to base due to the damage sustained. In consideration of the fact that Vishnyakov fired at the enemy aircraft he was pursuing at a distance of around 800 meters, the aircraft he hit was most likely No. A77-17 or No. A77-982, which were damaged in the battle but eventually returned to service. The next day he gained another credited aerial victory; there he led a group of 18 MiGs over Pyongyang, where they intercepted 16 F-84s at an altitude of 4,000 meters at 10:42 AM, which they subsequently dispersed and claimed to have shot down three of. However, it is unclear exactly which aircraft, if at all, that Vishnyakov show down that day. Over the next several days he tallied his last two aerial victories. On 5 December, Vishnyakov led a group of 22 MiGs in intercepting a group of 12 F-80s and 4 F-84s over Dzyunsen. With cover provided by other aircraft in his unit, he pursued an F-84 and shot it down, presumably F-84E 49-2415 piloted by Hugh Larkin, who parachuted out of his stricken plane and declared missing. Several days later on 8 December he claimed his last aerial victory in Korea, having led 20 MiGs from his regiment in a dogfight with 24 F-86s. In the resulting battle, Vishnyakov and two other Soviet pilots claimed aerial victories, but American records indicate the loss of only one F-86 from that encounter, F-86E 50-622, so it is unclear which Soviet pilot or pilots was responsible for it. Throughout the war he flew approximately 100 sorties, engaged in 36 aerial battles, and claimed six aerial victories.
