London - Manchester City have trimmed Chelsea's Premier League lead to three points with a 1-0 win over Everton on Saturday, but an injury to striker Sergio Aguero rendered victory bittersweet.
City capitalised on Chelsea's 2-1 defeat at Newcastle United earlier in the day to halve the London club's advantage at the summit thanks to Yaya Toure's 24th-minute penalty at the Etihad Stadium.
However, the points came at a price for the champions after a knee injury to Aguero early in the game saw him withdrawn in visible distress.
City recalled Eliaquim Mangala in defence after a one-match suspension, while midfielders Fernando and James Milner were also named in the starting line-up as coach Manuel Pellegrini made three changes.
Everton manager Roberto Martinez left out midfield playmaker Ross Barkley, with experienced forward Samuel Eto'o preferred to offer support to striker Romelu Lukaku.
The injury to Aguero occurred in the second minute when he jarred his left knee awkwardly as he stretched for the ball on the edge of the Everton penalty area.
The Argentina international, who had scored 11 goals in his previous nine league games, limped off with tears in his eyes and was replaced by 18-year-old striker Jose Pozo.
Pellegrini had claimed in his programme notes that "the team is not all about Sergio", but in the period immediately after his exit, they lacked a focal point in attack.
However, City were handed an opportunity to take the lead from the penalty spot when James Milner intercepted Gareth Barry's pass and was nudged over by visiting captain Phil Jagielka after he burst into the box.
Toure duly stepped up and although Everton goalkeeper Tim Howard went the right way, the Ivory Coast international's shot into the bottom-left corner of the net was too powerful and too accurate.
Everton enjoyed more possession as the first half wore on and shortly before half-time the ball fell on the edge of the area for Kevin Mirallas, who saw his shot closed down by Fernando.
The hosts should have doubled their advantage just after the interval when Milner escaped down the left and crossed for Pozo, but his goal-bound effort was saved by the leg of Howard.
Martinez introduced Barkley for Muhamed Besic on the hour-mark in a bid to give his side more attacking threat in the final third of the pitch, while Pellegrini replaced Pozo with the more experienced Edin Dzeko.
Everton certainly showed more ambition as they sensed they could get something out of the game, but they struggled to penetrate a disciplined City rearguard.
Eto'o won a free-kick in a dangerous position with 20 minutes left, but Mirallas saw his effort strike the top of the City wall and go over the bar.
Milner, who had been City's most impressive player, then had a chance to make the latter stages more comfortable for City when he seized on Dzeko's knock-down inside the area, only to slice his volley wide.
Everton created their best chance in the 82nd minute when Barry's pinpoint pass was deftly flicked on by Eto'o into the path of Lukaku, but Joe Hart produced a superb, diving save to repel his fierce, angled shot.
Martinez's side pressed for an equaliser in the five minutes of injury time added on at the end, but City's defence stood firm.