Liverpool's Champions League aspirations suffered a serious blow when they slipped to a 1-0 defeat away to Wigan Athletic on Monday.
Goalkeeper De Gea was forced to leave the field during Spain's Euro 2020 qualifier against Sweden on Tuesday.
Liverpool opened up a seven-point gap at the top of the English Premier League with a 1-0 win at Brighton & Hove Albion on Saturday, while Arsenal's poor away form continued with a 1-0 defeat at West Ham United.
Liverpool's livewire Sadio Mane scored one goal and played a crucial part in the other as they reclaimed the Premier League's top spot with a scrappy 2-1 win at second bottom Fulham on Sunday.
Roberto Firmino struck a stoppage-time winner as Liverpool beat Paris St Germain 3-2 at Anfield on Tuesday after Kylian Mbappe looked to have secured a point for the French side in a compelling Champions League Group C clash.
Images from the English Premier League matches played on Saturday
While the signing of a hard-working player who won two Premier League titles at City in five years since joining from Aston Villa is a coup for Liverpool, it also signifies the start of a squad makeover at City.
Liverpool's hopes of qualifying for the Champions League all but ended.
News of all that's transpired on and off the football field
Liverpool survived a late spell of Everton pressure to stretch their record unbeaten run in Merseyside derbies to 17 games
Inter Milan face Barcelona, Tottenham Hotspur and PSV Eindhoven in Group B which features three former European champions.
'I think 70-80 percent of the goals we have conceded are from set pieces. But they are all different and we are still working on it and we defended against Manchester United brilliantly'
Manchester United bolstered their squad with a flurry of transfer deadline day signings, Manchester City and Liverpool also splashed out while ambitious Brighton & Hove Albion sealed an audacious loan deal for Barcelona's Ansu Fati on Friday.
Talking about the ICC T20 World Cup in the West Indies/US this year and inclusion in 2028 Los Angeles Olympics, he said that the T20 World Cup in New York will be driven by expats.
The brilliance of Chelsea's Eden Hazard ended Liverpool's 100 percent start to the season as Maurizio Sarri's side enjoyed a 2-1 win at Anfield in the League Cup third round on Wednesday.
Liverpool's chief executive says the 60-70-million-pound cost of redeveloping the Anfield Road end of the club's iconic stadium is difficult to justify as a business deal. Ian Ayre told a meeting of Liverpool Supporters' Committee (LSC) that it could take 15 years to pay back, which he said was "not a smart investment for the business". Liverpool opened their redeveloped Main Stand earlier this season, raising seating capacity to more than 54,000, and have outline planning permission to extend Anfield Road by a further 4,800.
Former Manchester United manager Alex Ferguson said he was worried about the impact manager Juergen Klopp was having at his old team's great rivals Liverpool.
Liverpool took the lead against West Ham United but then had to come from behind in another game of thrills and spills for Juergen Klopp's unpredictable side who where held to a 2-2 home draw in the Premier League on Sunday.
The gifted 23-year-old attacking midfielder is moving to Anfield from Germany's Hoffenheim, where he played since 2010, scoring 47 goals in 151 appearances.
Liverpool, inspired by two-goal Egyptian Mohamed Salah, took a big step towards the Champions League final with a 5-2 win over AS Roma in their semi-final, first leg at Anfield on Tuesday.
Liverpool's UEFA Champions League challenge ended in a 1-1 draw against FC Basel, who booked their spot in the last 16.
In their first match since manager Claudio Ranieri was sacked after five successive defeats in which they failed to score a goal, Leicester produced the kind of vibrant display that carried them to glory last May.
Photos from the Premier League matches played on Sunday
Liverpool did not reveal the transfer fee but Southampton announced it was "a new world-record for a defender" with English media reporting that it was a 75 million pounds ($100.49 million) deal.
Liverpool manager Juergen Klopp wants his players to be "angry" and guard against complacency when they entertain promoted HullCity on Saturday.
Arsenal suffered another painful Premier League defeat as Swansea City capitalised on some glaring errors to win 3-1 on Tuesday, boosting their survival hopes and denting the visitors' top four chances.
Images from the Premier League matches played on Saturday, March 9.
Jurgen Klopp has agreed a contract extension with Liverpool until 2024
Real Madrid beat holders Manchester City in an edge-of-your-seat 4-3 shootout victory to reach the semi-finals of the Champions League.
A stunning strike from Jordan Henderson helped Liverpool secure a comfortable 2-1 win at Chelsea on Friday that ended the London club's unbeaten start to the season and underlined the growing potential of Juergen Klopp's side.
Images from the English Premier League matches played on Sunday
Liverpool striker Daniel Sturridge has had successful surgery on a hip problem that effectively ended his season, he said on social media on Tuesday.
Liverpool and Manchester United have warned fans that they will be removed from Anfield and could face criminal charges if found engaging in "offensive or discriminatory behaviour" in Monday's Premier League clash.
Images from Saturday's action in the Premier League.
IMAGES from the English Premier League matches played on Sunday.
"Liverpool FC are delighted to announce that they have agreed personal terms with Danny Ings and, subject to a medical, the striker will join the club on July 1 after his contract with Burnley has expired," the club said on their website (www.liverpoolfc.com).
The fifth and final Test is still two days away but thousands of English fans have flocked to the hill station.
If anyone was still wondering why Liverpool spurned Barcelona's bids for Brazilian playmaker Philippe Coutinho, his part in Saturday's 3-2 win over Leicester City provided the answer.
After the Champions League game, Liverpool host Arsenal in the league on Sunday.
Juergen Klopp named Philippe Coutinho as captain and the Brazilian curled a sublime effort into the top corner with the home side's first real attacking foray after just six minutes.