Harry Poole
BBC Sport at Wimbledon

Confirmation that this is the hottest opening day in Wimbledon's history.

Air temperature on the grounds had reached 31.4C by 14:00 BST, surpassing the previous record at the start of the Championships, which was the 29.3C set in 2001.

However, the heat rule has not yet been enforced because Wimbledon do not measure the 'heat stress' on the air temperature alone.

Wimbledon uses the Wet Bulb Globe Temperature (WBGT) heat index to determine when a 10-minute break for players is brought in, which combines air temperature, humidity and surface temperature readings.

The next reading will be taken at 5pm.

Image source, Getty Images

The double faults continue to pile up for Jacob Fearnley and they are coming at really costly moments.

After dropping the first set in that fashion, he drops serve to hand Joao Fonseca control of the second set.

Image source, Getty Images

Hannah Klugman, who turned 16 in February, has been rewarded with a main-draw wildcard for Wimbledon after demonstrating her potential over the past few years.

In 2023, the English player won the prestigious Orange Bowl junior championships in Florida, emulating the likes of Coco Gauff, Chris Evert and Caroline Wozniacki.

She works with coach Ben Haran out of Reed's School - which also nurtured Jack Draper and Tim Henman - and practises at the National Tennis Centre.

Spending two months preparing on clay - including time at Rafael Nadal's academy - fuelled her run to the Roland Garros final, but her solidity from the baseline and touch at the net works well on the grass.

Klugman has deferred her GCSEs until November to focus on tennis this summer.

She faces 2021 US Open runner-up Leylah Fernandez in her debut appearance at a Grand Slam.

Fabio Fognini has levelled it up at one set all!

Carlos Alcaraz saves three of the four set points, the third with a brilliant backhand overhead volley.

But he then misses what appears a far simpler shot after being brought in to the net.

The crowd rises to Fognini. An excellent set from the experienced Italian.

Cameron Norrie's recent upturn in form continues at Wimbledon, following his run to the last 16 of the French Open a few weeks ago.

It took a little more than three hours for him to get past veteran Spaniard Roberto Bautista Agut, but the Brit comes through that stern test and will face American 12th seed Frances Tiafoe in the second round on Wednesday.

Jacob Fearnley finally halts Joao Fonseca's run of winning 15 consecutive points.

But he trails 40-15 and is on the ropes.

Brilliant return from Fabio Fognini.

It gives Carlos Alcaraz a tricky half-volley... and he puts it wide.

A big serve follows from the Italian and he has four set points...

Gary Rose
BBC Sport at Wimbledon

That was nine points in a row lost by Jacob Fearnley there, having at one point looked primed to get the break and serve for the set. Instead he's lost the first set and is wobbling at the start of this second. How quickly things can change in tennis.

Joao Fonseca continues building momentum as he wraps up a third successive game and this time to love.

Is this the moment Fonseca puts his foot down?

Alexei Popyrin is on the ropes...

Arthur Fery once again putting pressure on the Australian's serve and he brings up a match point at 30-40.

He can't take it, however, and it is a let off for Popyrin as Fery's shot flies wide.

Popyrin then misses chances to hold and the British wildcard has another chance...

Jonathan Jurejko
BBC Sport senior tennis reporter at Wimbledon

Those two artists know how to paint a beautiful picture of their sport.

Alcaraz and Fognini trade flicks and licks with their one-handed backhands in a beautiful exchange at the net.

That's until Alcaraz has the chance to sledgehammer an overhead.

Fognini has a lot of support on Centre Court, which seems to believe the veteran Italian - playing in his final Wimbledon - has earned the right to level this match.

Early mini-break for Fabio Fognini after a double fault from Carlos Alcaraz.

That serve has been a real issue for the defending champion so far.

Fognini pushes home his advantage with a couple of hefty serves to move 4-1 ahead in the breaker.

A great forehand winner down the line earns Cameron Norrie another mini-break to go 4-3 up, and the Brit follows it up with two more winners on his own serve.

Three match points for the Brit...

Image source, Getty Images

Stefanos Tsitsipas has been forced to retire on Court 12 after receiving an on-court medical timeout. However, an upset was already brewing out on court after French qualifier Valentin Royver took the first set 6-3.

The 24th seed did choose to play on after initial treatment on his back but went on to lose the second set 6-2. He could be seen speaking to his new coach Goran Ivanisevic during the break in play, before making the tough decision to call time on his Wimbledon bid.

Danish eighth seed Holger Rune is in action over on Court Three. The Dane opened up a 6-4 6-4 lead over Nicolas Jarry, but the Chilean has just claimed the third set 7-5 to spice things up.

Elsewhere, Australian Open winner and sixth seed Madison Keys has started her next Grand Slam bid against Elena-Gabriela Ruse on Court Two.

Oh no.

Another double fault from Jacob Fearnley and Joao Fonseca takes the first set.

That's Fearnley's fifth double fault of the match.

Image source, PA Media

We're going to a tie-break.

A superb point finishes the game with Fabio Fognini nailing a forehand down the line to draw gasps from the Centre Court crowd.

But Carlos Alcaraz get it back, held firm then won the point at the net.

Huge hitting from both players in the early stages of the fourth-set tie-break.

Cameron Norrie and Roberto Bautista Agut swap a mini-break apiece and it's 3-3 at the first change of ends.

Jacob Fearnley really is serving to stay in the set.

Fearnley trails 40-0 with another forehand crashing into the net.