Arsenal's Premier League title charge faced a nervous moment on Saturday as Jurrien Timber was withdrawn prematurely during their clash against Everton at the Emirates Stadium. The versatile defender appeared to pick up a knock midway through the first half, forcing Mikel Arteta into an unplanned tactical reshuffle.The injury occurred during a period where Everton were beginning to grow into the game, frustrating the home side with a disciplined defensive display. Timber, who has been essential to Arsenal's defensive solidity this season, was seen struggling before the decision was made to bring him off. The nature of the injury was not immediately clear, but the fact that he could not make it to the half-time whistle will be a major worry for the Gunners' coaching staff.Following the forced substitution, Arsenal struggled to regain the fluid rhythm they displayed in the opening exchanges. The Toffees, led by David Moyes, sensed an opportunity to exploit the disruption in the Arsenal backline. Despite the Gunners dominating possession, they found clear-cut chances hard to come by, with Everton looking increasingly dangerous on the counter-attack through the likes of Kiernan Dewsbury-Hall.The contest appeared destined to end in a goalless draw until the closing stages, when Swedish striker Viktor Gyokeres broke the deadlock in the 89th minute. A cross from the right was misjudged by Everton Pickford, allowing Gyokeres to collect the loose ball and calmly finish into the empty net.Arsenal sealed the result deep into stoppage time as youngster Max Dowman struck in the 97th minute, capitalising on Pickford’s advanced position to finish off a swift counterattack and secure all three points for the Gunners.Add GOAL.com as a preferred source on Google to see more of our reportingFor Mikel Arteta, losing a player of Timber's caliber during the business end of the season is a nightmare scenario. With Manchester City continuing to breathe down their necks in the table, any prolonged absence for the Dutchman could have massive implications. The Gunners have relied on a settled back four for much of the campaign, and having to integrate Mosquera so suddenly tests the depth of the squad at a pivotal moment.