Olivier Giroud and Santi Cazorla both scored twice as Arsenal closed back up on the Barclays Premier League's top four with a 4-1 win over Newcastle at the Emirates Stadium.
Arsenal took the lead after 15 minutes when right-back Hector Bellerin won the ball in midfield, before it went out to Sanchez, one of several players rested in midweek.
The Chile forward held up possession on the right before chipping the ball across the six-yard box, where Giroud powered a header into the top-right corner.
The hosts doubled their lead after 54 minutes. Sanchez played a sliderule pass into the Newcastle penalty area, which Cazorla gathered and clipped a sublime finish into the far corner to celebrate his 30th birthday in style.
Before Newcastle could regroup, it was 3-0 after 58 minutes.
Bellerin got to the right touchline before crossing for Giroud, who expertly guided the ball past Alnwick at the near post with the outside of his left boot.
Newcastle reduced the arrears after 63 minutes when Perez headed in a free-kick from Jack Colback.
Arsenal soon regained composure, with Cazorla completing the scoring with a penalty two minutes from time.
Eden Hazard and Diego Costa scored as Chelsea won 2-0 at home to Hull City.
Jose Mourinho's side went ahead in the seventh minute at Stamford Bridge, with Hazard ghosting in from the right flank to head home Oscar's in-swinging cross from the left.
Costa made it 2-0 eight minutes later, gathering a pass from the influential Hazard and drilling a shot past Allan McGregor to claim his 12th goal of the campaign.
Manchester City registered a seventh successive win in all competitions, but victory against Leicester City came at the cost of injuries to striker Dzeko and captain Kompany.
Having previously lost top scorer Sergio Aguero to a knee injury that will keep him out until next year, City saw Dzeko withdraw from the starting XI after hurting himself in the warm-up.
It meant that 18-year-old Spaniard Jose Pozo started up front on his own, but after a laboured start, the champions went ahead in the 40th minute when Frank Lampard tucked away a pass from Samir Nasri.
It was the former Chelsea midfielder's 175th league goal, taking him level with Arsenal great Thierry Henry in fourth place in the all-time Premier League scoring chart.
Meanwhile, West Ham United squandered an opportunity to claim third place after being held to a 1-1 draw at Sunderland. Stewart Downing equalised for the visitors with a low, deflected shot shortly after Jordi Gomez had put the hosts ahead from the penalty spot in the 22nd minute.
Burnley climbed out of the relegation zone by beating Southampton 1-0 at Turf Moor.
Southampton winger Dusan Tadic saw a penalty saved by Tom Heaton, enabling Ashley Barnes to claim the winning goal with a deflected shot 17 minutes from time.
Craig Gardner scored the only goal as West Bromwich Albion won 1-0 at home to Aston Villa, who had West Brom old boy Kieran Richardson dismissed for a studs-up lunge on Stephane Sessegnon.
Elsewhere, Stoke City striker Peter Crouch swiftly cancelled out a headed 11th-minute opener by James McArthur as Mark Hughes's team claimed a 1-1 draw at Crystal Palace.