Match ends, Manchester City 3, West Bromwich Albion 0.
Manchester City moved 15 points clear at the top of the Premier League by outclassing West Brom at Etihad Stadium.
Fernandinho slipped home a finish from Kevin de Bruyne's surgical through ball to put the hosts ahead during a dominant first-half performance.
There was no let-up after the break and De Bruyne rounded off a slick counter-attack by tapping in the second from Raheem Sterling's pass.
Sterling then set up Aguero for the third with a cute reverse ball in the last minute of normal time.
West Brom only mustered their first effort on goal in the 88th minute after on-loan striker Daniel Sturridge was brought off the bench for his debut.
The result means the Baggies remain three points adrift at the bottom of the table, after Swansea's win over Arsenal on Tuesday.
City underlined the gulf in class and league position between the two sides by carving out chance after chance, with De Bruyne and Aguero guilty of misses among 18 efforts on goal.
One possible blemish on the evening for the hosts is the prospect of retrospective action being taken against Fernandinho after the Brazilian escaped any punishment for planting his foot onto the thigh of the prone Grzegorz Krychowiak in the first half.
However, West Brom were extremely fortunate that substitute Matt Phillips was allowed to see the match through to the final whistle after a thigh-high challenge on 18-year-old City substitute Brahim Diaz that only earned a yellow card.
Stylish Laporte catches the eye
With John Stones unwell and Vincent Kompany rested, defender Aymeric Laporte was brought in for an earlier-than-expected debut.
His club record £57m move from Athletic Bilbao was only confirmed on Tuesday, but the Baggies provided the ideal opportunity for the 24-year-old centre-back to ease himself into Premier League life.
He had plenty of time to step into midfield and, under little pressure, prompt the attack. Of City's outfield starters, only Bernardo Silva was more accurate with his passing.
Salomon Rondon's opportunities to test the Frenchman physically were few and far between, but Laporte gave as good as he got when the pair tangled in the second half.
Centre-back is a position that has consumed much of City's cash and attention in recent years. The signings of Stones, Nicolas Otamendi, Eliaquim Mangala, Matija Nastasic and Stefan Savic have eaten up about £140m of the club's substantial reserves.
Tougher tests await but Laporte - the most expensive of the lot - did nothing wrong on his debut.
West Brom wilt in Etihad cauldron
West Brom came into the game on the back of three wins and a draw from their past four games, but their mini-revival never seemed likely to survive the Premier League's toughest assignment.
Alan Pardew's side were penned back in their own half by near-constant City possession and pressure.
Their cause was not helped by Krychowiak hobbling to the sidelines in the wake of his skirmish with Fernandinho.
But their limits were summed up in the build-up to City's second as James McClean tried, and failed, to halt the counter-attacking De Bruyne with a cynical sliding challenge. As City celebrated, referee Bobby Madley showed the Republic of Ireland winger yellow.
Sturridge - back at the club where he began his career - showed some nice touches after 78th-minute introduction, freeing Phillips with a clever, scooped pass and shooting narrowly wide after springing City's offside trap.
Whether his sporadic moments of high quality are what West Brom need for the relegation fight to come remains to be seen.
Man of the match - Kevin de Bruyne (Manchester City)
'Laporte's amazing, amazing performance' - what they said
Manchester City manager Pep Guardiola: "Nice performance, top performance, deserved to win. Three more points.
"All season Kevin de Bruyne has played an outstanding level. If one of the best players runs like Kevin does, the rest follow him."
On Matt Phillips' challenge on Brahim Diaz: "I just had a nice chat with the official. We have a different opinion, I understand what they say but I disagree. I said what I said, insisting the same. It is what it is. We can have different opinions but in the end always respect for what they do."
On Aymeric Laporte's debut: "Yesterday he made the first training session, just passed the ball, but today we saw how good he is. He made an amazing, amazing performance. We are so happy for him."
West Brom manager Alan Pardew: "We had one or two senior players missing tonight which was crucial for us. We could not find a way to hurt them.
"I thought our two strikers did really well tonight, as our keeper did. Daniel Sturridge is a poacher, he almost scored. He will hopefully be a big player we just want to keep him fit.
"Manchester City were outstanding at times tonight. As a manager I just said to the players hopefully we don't meet them too often.
"We know we have the quality to get out of trouble, we just need a little bit of luck, get the goals at the right times and have good game management."
De Bruyne ahead of Messi, Neymar and Ozil - match stats
- Man City have won their past 13 league games in a row against West Brom, their longest such run against a single opponent in their history.
- Indeed, this is also West Brom's longest losing streak against a single team in their league history.
- De Bruyne provided his 38th league assist since his Man City debut in September 2015, at least four more than any other player in Europe's big five leagues (Lionel Messi, Neymar and Mesut Ozil with 34).
- Sterling (14 goals, 6 assists) became the fourth Premier League player to have a hand in 20+ goals this season, after Mohamed Salah (25), Harry Kane (22) and Sergio Aguero (22).
- Aguero has had a hand in 12 goals in 11 Premier League games against the Baggies (8 goals, 4 assists).
- West Brom have won only one of their past 22 Premier League games on the road (D8 L13), winning 1-0 at Burnley in August.
Manchester City travel to Burnley in Saturday's lunchtime kick-off in the Premier League, while West Brom welcome Southampton in a 15:00 GMT kick-off on the same day.
- 17De BruyneSubstituted forDiazat 78'minutes
- 21SilvaBooked at 32minsSubstituted forGündoganat 39'minutes
- 20Bernardo Silva
- 42Y Touré
- 28FieldSubstituted forPhillipsat 55'minutesBooked at 85mins
- 20KrychowiakSubstituted forBarryat 33'minutes
- 14McCleanBooked at 68mins
- 9RondónBooked at 75minsSubstituted forSturridgeat 78'minutes
- Robert Madley
- Shots on Target
Second Half ends, Manchester City 3, West Bromwich Albion 0.
Attempt missed. Brahim Diaz (Manchester City) left footed shot from the left side of the box is just a bit too high.
Attempt saved. Matt Phillips (West Bromwich Albion) left footed shot from the left side of the box is saved in the centre of the goal. Assisted by Jay Rodriguez.
Goal! Manchester City 3, West Bromwich Albion 0. Sergio Agüero (Manchester City) right footed shot from the right side of the box to the bottom left corner. Assisted by Raheem Sterling with a through ball.
Attempt missed. Daniel Sturridge (West Bromwich Albion) left footed shot from the left side of the box is close, but misses to the left.
Attempt blocked. Daniel Sturridge (West Bromwich Albion) left footed shot from outside the box is blocked. Assisted by Gareth Barry.
Corner, Manchester City. Conceded by Claudio Yacob.
Corner, Manchester City. Conceded by Gareth Barry.
Matt Phillips (West Bromwich Albion) is shown the yellow card for a bad foul.
Brahim Diaz (Manchester City) wins a free kick on the left wing.
Foul by Matt Phillips (West Bromwich Albion).
Attempt missed. Bernardo Silva (Manchester City) left footed shot from the centre of the box is close, but misses to the left following a fast break.
Attempt saved. Brahim Diaz (Manchester City) right footed shot from the centre of the box is saved in the bottom right corner. Assisted by Raheem Sterling.
Corner, West Bromwich Albion. Conceded by Nicolás Otamendi.
Hand ball by Kyle Walker (Manchester City).
Attempt missed. Kyle Walker (Manchester City) right footed shot from the right side of the box is just a bit too high.
Bernardo Silva (Manchester City) wins a free kick in the defensive half.
Foul by James McClean (West Bromwich Albion).
Substitution, West Bromwich Albion. Daniel Sturridge replaces Salomón Rondón.