The 9-time Olympic champion, Felix, in cold conditions clocked 51.47 to finish 0.07 seconds ahead of Poland's Justyna Saint-Ersetic.
Watch Allyson Felix win 400m in Chorzow
Poland's Konrad Bukowiecki prevailed in the men's shot put with a huge personal best and European U23 record throw of 22.25m. The 22-year-old Bukowiecki defeated reigning World champion Tom Walsh from New Zealand who threw 21.90 to take 2nd place.
Baham's Rio Olympic Games bronze medalist Steven Gardiner clocked his season's best 44.14 to win the men's 400m.
American Shannon Osika shaved almost 3 seconds from her personal best to win the women's 1500m in 4:01.80.
Polish finished 1-2-3 in a very dramatic 1000m race. Marcin Lewandowski kicked hard to win the race in 2:21.01. Adam Kszczot finished in second in 2:21.42 while Michal Rozmys took third in 2:21.72.
Ewa Swoboda of Poland comfortably took the women's 100m in 11.29 while the men's race won American sprinter Isiah Young in 10.22 seconds.
Piotr Lisek cleared 5.82m for the win in the men's pole vault.