A stunning second half strike by the Hockeyroos co-captain sparked Australia's 6-1 romp over Spain at the Beijing Olympics today.

However, none of her teammates knew the goal's true significance.

"It was a bit of a special one for me. My grandma passed away on the day of my last match (on Sunday) and I didn't find out until after," Hudson said.

"When I scored, all I could do was look to the heavens and say 'thanks'.

"She was my biggest fan. I went out and told my dad that I would play with her in my heart today.

"She had a great life and she will be proud up there in heaven. Not just of me but of all the girls."

Locked up at 1-1 after weathering a stunning early Spanish assault, Australia needed something special in the second half at the Olympic Green Hockey Stadium.

Enter Hudson.

The three-time Olympian weaved through three opponents before striking truly from the top of the circle in the 47th minute to give Australia the lead for the first time in the match.

Hudson raised her fists triumphantly.

Spain dropped their heads.

Then the floodgates opened.

Three goals in 16 minutes followed and the under-rated Hockeyroos remained unbeaten at Beijing after two games.

Major milestones loom for Hudson, a veteran of 15 years on the international stage.

She becomes the first Hockeyroo - and second Australian hockey player overall - to reach 300 internationals in their next clash against South Africa on Thursday.

And the Queenslander is aiming to become just the fourth Hockeyroo to break through the 100-goal barrier at the Olympics.

But nothing will beat goal No.98 for Hudson - the one she dedicated to her "Grandma Mott".

"None of the girls knew about it. I kept it quiet. It's never good news," Hudson said.

"You could make it something that upsets you or you can turn it into something positive."

It was the second straight game in which Hudson provided the Hockeyroos' spark.

Her solo effort proved the turning point as Australia came from three goals down at halftime to overcome South Korea 5-4 in their Olympic opener.

"I've been disappointed with how I've played in the last two years," Hudson said.

"Before the Olympics, (coach) Frank (Murray) took me aside and said 'I have so much belief in you'.
"At the end of the match, he came up and grabbed me by the shoulders and said 'that's why we picked you'."

Murray said Hudson's leadership was just what his young Hockeyroos needed as they rebuild after a disappointing fifth place at Athens.

"That second goal by Nikki was a very good goal and that inspires the younger players," he said.

The three-time Olympic champions were caught off guard by the world No.8 Spaniards, trailing 1-0 after six minutes and appearing to have conceded another in the 21st.

However, fullback Maria Romagosa's strike from a penalty corner was disallowed by the video umpire for dangerous play.