Chelsea will aim to cement their position atop the Premier League rankings but face no easy task in doing so this weekend against a fired-up Brentford in Saturday's London derby.
Thomas Tuchel's side eased past Southampton before the international break, while the Bees got the better of West Ham United 2-1.
Chelsea have been handed a major boost with the news that Lukaku is fit, but the leaders can take nothing for granted against a Brentford side fired up in front of their own fans.
Tuchel has far more fitness concerns to deal with than he would have liked at this stage, and while we still expect the Blues to just about pull through, Frank's side are sure to give them a scare or two.
Seeking to establish themselves as Premier League mainstays during the first few weeks of the season, Brentford's success story is earning a few more chapters, with the Bees following up their pulsating 3-3 draw with Liverpool with a 2-1 win at Europa League side West Ham earlier this month.
Jarrod Bowen's 80th-minute strike appeared to have rescued a point for West Ham following Bryan Mbeumo's opener in the first half, but lightning struck twice for substitute Yoane Wissa, who netted with virtually the last kick of the game to propel the Bees to another top-flight win.
Brentford's stellar start to the season is showing no signs of slowing down anytime soon, and having taken seven points from their last three games, Thomas Frank's side have risen to seventh in the table - above the likes of Leicester City, Arsenal and Tottenham Hotspur.
The hosts' only defeat so far this season did come on home soil, though - 1-0 against another surprise package in Brighton &amp; Hove Albion - but having beaten Arsenal and drawn with Liverpool on their own patch, Chelsea can hardly travel across the capital expecting a routine three points.
In addition to their wins over Arsenal and West Ham, Brentford's goalless draw with Crystal Palace means that they have earned a place in the Premier League history books as the first side to go unbeaten in their first three London derbies in the competition.
After back-to-back 1-0 defeats to Manchester City and Juventus to round off an otherwise successful September, Chelsea turned on the style to comfortably see off Southampton and head into the international break with something to build on.
Trevoh Chalobah once again justified his starting place with the opening goal in the ninth minute of the encounter, before James Ward-Prowse's penalty made things interesting, but Timo Werner and Ben Chilwell bagged two quickfire late goals to sink the Saints.
With Liverpool, Manchester City, Manchester United and Everton all playing out draws in gameweek seven, Chelsea's comfortable win over Southampton has seen them surge to the top of the rankings with 16 points taken from a possible 21 so far this term.
Desperate to add a top-flight title to his European crown at Stamford Bridge, Tuchel's renowned staunch defence has conceded a joint-low three league goals this term - level with champions Man City - and the German coach has lost just one of his 12 away games in the Premier League since taking over at Chelsea.
Not since the 1938-39 season have Brentford prevailed against Chelsea in any competition, with the Blues marching to successive 4-0 FA Cup wins in the 2012-13 and 2016-17 seasons, although the victory in the former season came during a replay after an initial 2-2 draw.
Shandon Baptiste was taken off in the first half against West Ham after dislocating his shoulder and will play no part here, while Mads Sorensen and Josh Dasilva remain absent for the long-term.
Kristoffer Ajer and Vitaly Janelt could return from thigh problems in time for this game, but the latter's potential absence would open up a spot for Mathias Jensen to start in midfield.
Wissa could hardly have done more in his quest for a starting place, but the ex-Lorient man would likely only be granted it if Frank opts to sacrifice a central midfielder, which seems unlikely against the league leaders.
Chelsea veteran Thiago Silva will not play given his late return from international duty, but Reece James and N'Golo Kante are back in training after recovering from an ankle injury and coronavirus respectively.
The Blues were handed an injury scare with Romelu Lukaku withdrawing from international duty due to muscular overload - but Tuchel has confirmed that the Belgian will play - while Antonio Rudiger and Christian Pulisic will also miss out.
Kai Havertz and Mason Mount were both named on the bench against the Saints but should be fine to start here, and Hakim Ziyech is a doubt with illness.
Brentford possible starting lineup:
Raya; Ajer, Jansson, Pinnock; Canos, Norgaard, Onyeka, Janelt, Henry; Toney, Mbeumo
Chelsea possible starting lineup:
Mendy; Azpilicueta, Chalobah, Christensen; James, Jorginho, Kante, Chilwell; Mount, Havertz; Lukaku