A:Was it a good game yesterday?
B:Well, the beginning was fine. We were playing well and we were winning, but then they scored four goals.
Why is it said "we were winning" here? Isn't "win" an instantaneous verb? Isn't it supposed to be an instantaneous verb without an "-ing" form? What does "winning" mean in this context? Is it the progressive tense indicating the future, or does it mean they were continuously winning over a period of time?