Walsh was at the heart of Chelsea's best moments against West Ham and her goal capped a brilliant performance.
The England midfielder had five shots, the most of any Chelsea player, finding the net with the only one on target.
She created three chances for her team-mates and won six of her nine duels in an all-action midfield display.
With the Lionesses in action against Greece in their Women's World Cup qualifying play-off matches later this month, Walsh's fine form could not have come at a better time for club and country.
"Keira is playing a little bit higher than last season," said Bompastor. "Her shot is so great so she is able to score.
"Right now it's good to have a player with confidence who brings us the solution to score goals, that's really important."
West Ham, on the other hand, failed to have any shots at all as they fell to their fourth defeat of the campaign.
Hammers boss Rita Guarino said: "We know we need to improve with how we retain the ball. When we win the ball, we need to try to find the space.
"We will work on that but it is not easy to solve the problem in the next few weeks."