Consider this description:
突然间眼前一花,身前三尺处已多了一人,正是游坦之。这一下来得大是出其不意,以丁春秋眼力之 锐,竟也没瞧清楚他是如何来的,心惊之下,不由得退了一步。
Originally, You Tanzhi was quite far from Ding Chunqiu (probably 20+ feet, inferred from how Ding Chunqiu later grabbed Ah Zi from 60+ feet away). He appeared out of nowhere to only 3 inches away from Ding. Ding was completely taken by You's Surprising Appearance.
Now, You appeared to let Ding strike first. If You had meant to strike Ding first, could he have KO'ed Ding, in a similar manner as Dongfang Bubai KO'ed MASTER OF WIND & THUNDER HALL Tong Baixiong?