It is worth noting that at the time of the Summit Series Anatoli Firsov was by far the most proven big game performer in European hockey. If we look at the scoring in games between the top 3 teams in Europe (USSR, CSSR and Sweden) over the last 4 major international tournaments of Firsovs international career (1969, 1970, 1971 World Championships and the 1972 Olympics) this is what we get.
Scoring against other Top 3 teams in the time frame between the 1969 WHC and the 1972 Olympics (sorted by PPG among players who played in at least 60 percent of the available games)
1 Anatoli Firsov: 13 gp, 10 g, 7 a, 17 pts (1.308)
2 Valeri Kharlamov: 14 gp, 7 g, 6 a, 13 pts (0.929)
3 Boris Mikhailov: 13 gp, 7 g, 3 a, 10 pts (0.769)
Goalscoring against Top 3 teams in the time frame between the 1969 WHC and the 1972 Olympics (sorted by GPG among players who played in at least 60 percent of the available games)
1 Anatoli Firsov: 13 gp, 10 g (0.769)
2 Boris Mikhailov: 13 gp, 7 g (0.538)
3 Valeri Kharlamov: 14 gp, 7 g (0.500)
As you can see Firsov was very clearly the most productive player in games between the top 3 teams in Europe during this time frame both when it comes to scoring and goalscoring. In fact Firsovs goalscoring stats alone would put him tied with Mikhailov for second place on the points per game list behind only Kharlamov and on top of being by far the most dominant goalscorer Firsov was also the second best playmaker in these games.