The Premier League are reported to have paid £26million to sign the 22-year-old, who appeared in all five of Uruguay's matches at the World Cup.
The club announced the signing on Tuesday afternoon, with Emery delighted to add Torreira to his squad.
While Chinyere wished him "immense success" during his time at the Emirates, Mario Piso already guaranteed a "great 2018/19" season. "We welcome Lucas to Arsenal and look forward to him joining us soon for pre-season".
On signing for the North London outfit, Guendouzi told the club's website: 'It's something I'm immensely proud of. It's a very positive thing that people want to welcome me.
How to watch the semi-finals
I pray and I would give anything in the world that this squad eventually "confines us to history". We want those who are 100-per-cent match fit.
Investigators probe scene of Wonderboom plane crash for clues
The plane had been due to fly later this week to Aviodrome via east Africa, through Egypt, Croatia, Austria to the Netherlands. The plane had the words "Martin's Air Charter" painted on it, which was a previous name of Dutch cargo airline Martinair.
"I want to win titles, titles, titles".
The former Sunderland player posted a photo on Instagram signing his deal, writing that "today is the start of a new chapter in my life".
The 5ft 6in holding midfielder flew to London earlier in the week to undergo a medical, and his acquisition will be seen as a huge boost to the club following the recent departure of Jack Wilshere to West Ham.
No official indication has been made over the length of the contract while the transfer remains subject to "regulatory" global clearance.
"I want to become part of the club's history and to achieve great things here", said midfielder Guendouzi.
Unai Emery insists new signing Matteo Guendouzi will fight for a first team place this season.
Hurricane Chris strengthens as it moves away from U.S.
Puerto Rico Governor Ricardo Rossello said the territory had opened more than 40 evacuation shelters for those in need. Hurricane Chris is expected to pass south of Nova Scotia on Thursday, creating high waves along the Atlantic coast.
Trump nominates Brett Kavanaugh to Supreme Court
Relishing the suspense, Trump insisted he still hadn't locked down his decision, which he wants to keep under wraps until a 9 p.m. Ahead of the announcement, three names surfaced as the contenders - Amy Coney Barrett , Kavanaugh and Raymond Kethledge .
UK woman dies after being exposed to nerve agent novichok
Russian state television reports on July 9 nonetheless continued to cast doubt on the British investigations into the poisonings. They are not showing any signs of having been exposed to the nerve agent, and are being screened as a precaution.
Croatia beats Russian Federation in shootout to reach semis
Modic will have to show leadership in Sochi if Croatia is to make it to the semi-finals for the second time in their history. Host Russia are set to face Croatia later today in the quarter finals of the world cup at the Fisht Stadium in Sochi .
Britain’s Prince Louis christened without Queen
Harry Aubrey-Fletcher: He went to Ludgrove School and Eton with William and his father is the Lord Lieutenant of Buckinghamshire. Royal fanatics have speculated that Kate Middleton paid a secret tribute to Princess Diana at the christening of Prince Louis .
Thailand Cave Rescue Latest: More Schoolboys Are Saved
Last night, Thai navy SEALs posted a celebratory note on their Facebook page, saying: "Have sweet dreams everyone". Monsoon flooding blocked their exit route and prevented rescuers from reaching them for almost 10 days.
Henderson hopeful on fitness for World Cup semi-final
England too left Italy 28 years ago feeling that the team featuring Gary Lineker and Paul Gascoigne could have gone all the way. As we regroup, he turns to me and says, "right that's enough, time to lift the tempo, let's get about them".
Truck driver charged in Canada hockey team crash with 16 dead
The tractor trailer he was driving crashed into a bus carrying members of the Humboldt Broncos junior hockey team, aged 16 to 21. Saskatchewan RCMP has announced that an arrest has been made in connection to the Humboldt bus crash, that killed 16 people .