Perhaps being an eternal optimist really does pay off.

For proof, look no further than United States Women's National Team head coach Pia Sundhage.

Three years after first taking charge of the senior side, the 51-year-old has led the US to its third FIFA Women's World Cup final in team history. The US is now poised for Sunday's titanic clash with sentimental favorites Japan.

It's the biggest match in a generation for the US, but if the team continues to take its cues from Sundhage's serene personality, the players will approach it with calmness. Sundhage expresses passion for her team with composed subtlety and even-handedness. She has never been one to remonstrate wildly on the sidelines or publicly berate players for substandard performances.

It's a relative serenity owed to the value the Sweden native puts in positive reinforcement, loyalty, and - perhaps above all else - endless optimism. That last item has proved crucial, as there have been reasons to feel a little downbeat about this US team over the past year.

The Americans endured a rocky World Cup qualifying campaign, one that saw them nearly miss out on this summer's tournament after a shock defeat to Mexico in regional qualifying. That preceded a series of uneven performances in friendlies during the lead-up to the World Cup.

Criticism began to get leveled at Sundhage for her ceaseless reliance on a flat 4-4-2, unchanging starting lineup and predictable substitution patterns. The team always set in up in the same way with the same players regardless of previous results or performances.

But the underwhelming friendlies proved to be little more than glorified scrimmages. In a move that both pleased and perhaps puzzled fans, Sundhage waited to make her alterations during the World Cup itself.

She's since been vindicated. Her decision to convert central striker Lauren Cheney to outside midfield has paid huge dividends. The 24-year-old has been one of the most effective midfielders of the tournament.

Cheney supplanted Megan Rapinoe, but the dynamic wide player has found new life as a super sub. It was Rapinoe's gloriously pin-point accurate pass that Abby Wambach headed in for the dramatic equalizer against Brazil.

It's a fighting spirit, displayed in both that match and in the semifinal against France, that seems to emanate from the top.

"If you have high expectations," Sundhage explains, "if you have positive expectations, very often (something positive) happens."

Even though the midfield still has a tendency to get ruffled at times, the team is performing as a cohesive unit. Sundhage deserves the credit for that. Promoting the right balance of team chemistry in the face of hardship is something she specializes in. She earned similar plaudits after the US defeated Brazil to claim the gold medal in the 2008 Summer Olympics.

At the time, the US had just emerged from a vortex of negativity put in motion after the team's humiliating 4-0 loss at the hands of Brazil in the semifinals of the 2007 FIFA Women's World Cup. Hope Solo's reaction to then-head coach Greg Ryan's decision to bench her for the match has been well-documented.

The U.S. Soccer Federation looked to swiftly turn the page on that notorious chapter of team history, electing to appoint someone who could usher in a new mentality and fresh perspective. It was a calculated risk, selecting someone unfamiliar with the United States' soccer culture, but a change of direction was needed, something Sundhage recognizes.

"I guess there's a reason they hired me from a foreign country," she said. "They wanted change. It was risky to make too big of a change, because then (the team) would lose a lot of confidence."

But that downturn never came. On the contrary, the US departed Beijing with both a gold medal and a measure of redemption. Sundhage earned her stripes, proving early on that successful players could also become successful coaches.

Her ability to adjust to new situations swiftly while remaining level-headed mirrors her decorated career as a player. Sundhage played as a forward, midfielder, and sweeper for both club and country. She was (and indeed, still is) considered a pioneer of women's soccer in her native Sweden. The imprint she left is etched in Sweden Women's National Team's history as she remains the country's all-time Women's World Cup leading goal-scorer.

And now Sundhage is one match away from leaving an indelible mark with the United States. The US' World Cup journey has been guided by Sundhage's unfailing optimism and unflappable persona, traits that have persisted despite a barrage of obstacles and criticisms.

"My glass is half full," Sundhage said, a strangely simple way of explaining such a successful approach. "I try to show (the team) what works."

It certainly has up to now. Showing the team what works may lead the US to the world title.