Jonathan Jurejko
BBC Sport at Wimbledon

This contest is going to be shown all over the world - including, thankfully, in New Zealand.

An issue with broadcasting rights meant Wimbledon was initially not shown on television in the Pacific nation.

A late deal saw the matches put on TVNZ+ - a streaming service similar to the BBC iPlayer - but it only had the world feed coverage, which did not show anything outside of Centre Court and Court One.

That meant Kiwi fans could not watch any of Sun's opening three matches on national television.

That changed when she played Emma Raducanu on Centre Court and means, at just gone 1am on Wednesday in New Zealand, there will be plenty staying up through the night to watch it.

Joe Rindl
BBC Sport at Wimbledon

Scenes!

Lulu Sun takes a thrilling set in exactly one hour with a peach of a drop-shot winner. Court One rises to its feet, people are whooping, whistling even.

It's pretty much a packed house in here now, and everybody has so far been treated to a classic.

Oh, and how's this for a story? A qualifier is a set away from reaching the semi-finals of Wimbledon, something we haven't seen since 1999.

It's fascinating stuff when the rallies get going between these two and it's been a staple of this match so far.

It's equally fascinating when Daniil Medvedev challenges a wrong call, and the Russian does so on this occasion to hold.

The first flicker of emotion from Lulu Sun as she plays an unstoppable cross-court backhand to make it 30-30.

But Donna Vekic is going nowhere. The Croatian is fighting to stay in this set and when Sun's backhand slice finds the net, Vekic has break point.

Sun saves it with a big serve and when Vekic goes long, the qualifier has a set point.

Taken in style! A fabulous drop shot puts Sun a set up.

Todd Woodbridge
Former Wimbledon doubles champion on BBC TV

Sinner doesn’t give you the time to implement what you would like. He’s so heavy on the ball and if you drop anything short he’s on top of you.

A backhand into the net from Jannik Sinner before a double fault gives Daniil Medvedev half a chance at 15-30.

But wait, Sinner challenges and it's in by quite a distance, so it's as you were at 15-15.

Two aces and an eye-catching forehand winner see the Italian go on to hold.

Martina Navratilova
Nine-time Wimbledon singles champion on BBC TV

It wasn’t a terrible game by Vekic but it was slightly loose. I think the scoreboard pressure got to her. The momentum just shifted and now Sun is in the driving seat.

Joe Rindl
BBC Sport at Wimbledon

Wow! After saving four break points this set, Lulu Sun needs just two chances to stun Donna Vekic on Court One.

A few in the crowd are on their feet. Earlier we even had one fan leading a chant of "let's go Lulu, let's go".

The New Zealander is getting more and more popular with every game.

Lulu Sun strikes first in the opening set.

The New Zealander brings up two break points and after going long on the first, sees Donna Vekic's wayward forward fly wide on the second.

Sun will serve the first set.

Todd Woodbridge
Former Wimbledon doubles champion on BBC TV

I think Sinner will come to the net when required. Daniil doesn’t want to come to the net and his transition can falter. He doesn’t know when to come in.

Daniil Medvedev gets the better of a 25-shot rally, coming into the net to seal the point with an emphatic smash.

Jannik Sinner hits the shot of the match so far, a deep forehand winner down the line, but it's in vain as he puts a backhand wide shortly after to give Medvedev the hold.

On we go.

From 0-30, Lulu Sun quickly reels off four points in a row to keep it on serve.

Donna Vekic had the chance to get after a second serve at 15-30 to really ramp up the pressure but perhaps tried to hit it too hard and a wild forehand flew into the crowd.

Donna Vekic crushes a backhand down the line to move up 0-30 on Lulu Sun's serve.

Is this the chance for the world number 37?

Jannik Sinner opens up the court with a deep forehand before coming into the net to smash a winner.

The Italian sees out the rest of the game with little trouble, holding to love.

Strong serving from Donna Vekic and she wraps up a straightforward hold by whipping a forehand down the line and past Lulu Sun.

Joe Rindl
BBC Sport at Wimbledon

While Lulu Sun keeps cool, calm and collected, Donna Vekic is old school, living for every big point.

After setting up game point with a cracking forehand down the line she roared "come on" and pumped her fist. She repeated the celebration after clinching her hold

I'm with Vekic on this one. If I was to ever win a service game under the roof at Wimbledon - and hey there's still time - I'd celebrate with everything I've got. Knee slide in the corner while screaming "let's go".

Anyway, what I'm trying to tell you, albeit very clumsily, is that this match is the biggest in both these players' careers, and they both have very different approaches to it.

Martina Navratilova
Nine-time Wimbledon singles champion on BBC TV

When your goal is to win majors [like Sun], when you get here you feel like you belong. You don’t shrug from the pressure because that’s what you want.

Daniil Medvedev showing both sides to his game with some monster serves and a delicate drop shot as the Russian breezes through with a hold to love.

Much more comfortable on serve for Lulu Sun this time.

With new balls at her disposal, the Kiwi left-hander holds to 15.

Ashleigh Barty
Three-time Grand Slam champion on BBC TV

Image source, Reuters

I think Vekic has used her serve very effectively today. I just have this inkling she is targeting the Sun backhand return.