Hundreds of thousands of other Black Caps supporters cheered him on from afar, soaking up the innings in front of TVs in bars and living rooms around the nation.
But one of the biggest cheers Guptill received was from his new wife, TV and radio host Laura McGoldrick, who wasn't shy in letting her emotions go during her husband's batting heroics.
"Watching her anxiety and her relief when he got 100 was one of the greatest things I've ever seen in my life," Stewart Wimms, who was sitting behind McGoldrick, said.
"She's down to her knuckles ... "
McGoldrick was one of the first to rise to her feet after her husband passed the 200 mark.
Her pride in the 28-year-old - whose selection in New Zealand's 15-man World Cup team had been questioned by some supporters - was all over her face.
Wimms also suffered for Guptill too. "I haven't got any nails left," he said.
But the post-Guptill innings words of the Kapiti Coast fan - who made a big sacrifice to watch yesterday's outstanding performance - summed it up as the nation prepares for Tuesday's semifinal against South Africa at Eden Park: "I have no superlatives.
"I've run out of words to say about how the Kiwis are performing," he said.
Wimms, who celebrates his birthday today, confessed he missed out on another special event to be at the match.
"I was supposed to be at my cousin's wedding. They gave me [their] blessing."
Watching the World Cup at home was something he'd treasure forever, especially after the Guptill-inspired demolition job.
"It's the best atmosphere I've ever seen in my life."
The omens were looking good early on in the capital yesterday when fans awoke to blazing sunshine.
The expectation could be seen on the faces of supporters as they made their way to Westpac Stadium; in buses from the city's suburbs it was a case of standing room only.
And on faces of fans running late, sprinting down Lambton Quay and nearby streets to the stadium, there was excitement and anticipation.
And Brendon McCullum's men didn't let down their followers.
As Guptill and his mates dined out on the Windies' bowling attack, fans gorged their way through food supplies at the venue, several forced to close after running out of grub.
Stadium chief executive Shane Harmon said the venue had experienced the "highest turnover" in its history.
Strangers shared hugs during Guptill's blazing knock, and again later in the evening when the Black Caps' bowling attack dismantled the West Indies, dismissing them for just 250 in the 31st over for a 143-run victory.
The new sporting bonds included Wimms befriending West Indies supporter Fitz Bowen, who moved to Wellington from Nottingham, England, 10 years ago.
Bowen said while he had copped a bit of ribbing over his side's World Cup exit, the conversations were all good natured as Kiwi fans soaked up the sensational summer of cricket.
"Everyone's always up for giving each other a wind-up," Bowen said.
But he warned that even if the Black Caps beat South Africa on Tuesday, they'd likely face a huge task in next Sunday's Cricket World Cup final in Melbourne.
"It'll be hard for any team to beat Australia, unfortunately." They have to beat India on Thursday first.
And last night, as the congratulations flowed for the stunning Black Caps, the jokes were also doing the rounds on Twitter.
A fake "sick note" supposedly signed by McCullum was being shared among fans who might need to be excused from the office on Tuesday.
"They may not be at the office, but rest assured they'll be putting in the hard yards at Eden Park, helping us get over the line against South Africa," it said.
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