It’s pitch 5. Which is clearly not a strike, as shown here:
There was a runner on first and nobody out in the top of the ninth when that horrendous call happened, and it was this horrendous:
According to @ESPNStatsInfo the strike 3 call on Kemp in the 9th inning had a 0.00 percent chance of being called a strike. (Based on history of that pitch)
— Jesse Rogers (@ESPNChiCubs) August 14, 2019
Now, would the Cubs have won that game if Kemp’s at-bat had continued? Of course, we’ll never know.