Why is "v" here if "After the fifth goal in the match they did not want to continue" is not correct?
You can't translate every word. Here "pokračovat v něčem" is "to continue something". It is not "pátý gól v zápase" but "pokračovat v zápase"="to continue the match".
"After the fifth goal they did not want to continue in the tournament" is not possible?
A tournament is turnaj, not zápas.