Chelsea secured a hard-fought 2-1 victory at home over West Ham United in a thrilling London derby fixture.The win ensured that Thomas Tuchel's team got back to winning ways after losing by 2-1 away to Southampton in their previous league game.Goals from Ben Chilwell and Kai Havertz ensured back-to-back home wins for the Blues in the current 2022-23 Premier League campaign.The result means that Chelsea is currently on 10 points in the league after six fixtures so far, winning three, drawing one, and losing two games.As expected, the London derby between Chelsea and West Ham United had a couple of major talking points. As such, this article will look at three positive and a couple of negative takes from the Blues' performance.Postivies from the game for ChelseaDespite being a hard fought victory for the Blues, there were a couple of positive notes from the teams' performance.#1 CharacterWest Ham United lose by 2-1 at Stamford BridgeOne major positive from Chelsea's 2-1 win against West Ham United was their show of character to turn the game around.The Blues went behind in the 63rd minute after Michail Antonio opened the scoring for the Hammers against the run of play.While it looked as though Tuchel's team would drop yet another crucial point this season, the Blues were able to put on a strong fight.Pys@CFCPysBack to Back 2-1 wins at Stamford Bridge in front of Todd Boehly, let’s make winning a regular occurrence again at home, something I never thought I’d say.4392244Back to Back 2-1 wins at Stamford Bridge in front of Todd Boehly, let’s make winning a regular occurrence again at home, something I never thought I’d say. https://t.co/JRlSBMbb0rUnlike previous games where Chelsea lost momentum after going behind, the Blues showed more than enough character against West Ham United.#2 Bench to the rescueHavertz scores his first league goal of the seasonAnother positive draw from Chelsea's hard fought victory against the Hammers at Stamford Bridge was the evidence of their strong bench.The Blues are currently one of the few teams in the league with huge squad depth. This played a key role in helping the team win three points.The game changers for Tuchel's team were substitutes Chilwell and Havertz, with both players getting on the scoresheet for the West London club.Frank Khalid@FrankKhalidUKBoth our subs turned this game around!!! Well done to both of them & especially Kai Havertz who some fans have been giving a hard time of late. Final score we win 2-1!!! Give me your thoughts on the game!!! #CHEWHU2333132Both our subs turned this game around!!! Well done to both of them & especially Kai Havertz who some fans have been giving a hard time of late. Final score we win 2-1!!! Give me your thoughts on the game!!! #CHEWHU https://t.co/JKwv6KpTi8This could be a huge factor for Tuchel this season. The German tactician has a huge amount of options to call upon when needed to change the outcome of the game.#3 Decent debut for Wesley FofanaFofana made his home debut for the BluesAnother positive from Chelsea's victory against West Ham United was the decent debut performance of Wesley Fofana.The Blues' new signing made his first official appearance for Tuchel's team after securing a big-money move from Leicester City.Despite not being able to help his team keep a clean sheet against the Hammers, Fofana was decent in the back three position.Pys@CFCPysWesley Fofana vs West Ham : 2 Clearances 3 tackles 6/8 totals duels won 6 ball recoveries 5 passes into final 3rd 102 Touches 90% pass accuracy Solid debut, @Wesley_Fofanaa 9292856Wesley Fofana vs West Ham : 2 Clearances 3 tackles 6/8 totals duels won 6 ball recoveries 5 passes into final 3rd 102 Touches 90% pass accuracy Solid debut, @Wesley_Fofanaa 💙 https://t.co/9TuktN9XXfThe 21-year-old defender made two clearances, three tackles, six ball recoveries, and also had a 90% pass accuracy on his Blues debut.Negatives from the gameThere were still a few concerns for Tuchel's team against West Ham United and here are two of them.#1 Defense exposed once againAntonio opened scoring for West Ham UnitedChelsea haven't really looked defensively solid this season, which seems to be a major concern considering how well they have faired under Tuchel.The Blues have so far kept just one clean sheet this campaign, conceding a whopping nine goals in six league games.Against West Ham United, their defensive fragilities were once again exposed as the Blues conceded yet again.B/R Football@brfootballOFFICIAL: Wesley Fofana joins Chelsea from Leicester on a seven-year deal.Their defense has a new look 363212519OFFICIAL: Wesley Fofana joins Chelsea from Leicester on a seven-year deal.Their defense has a new look 🔵 https://t.co/gt4yMrpruJTuchel's team's inability to deal with set-pieces this season was on display against the Hammers. The East London club scored from a corner kick which the Blues failed to deal with properly.Despite spending a combined total of £159 million this summer on defensive reinforcements, the Blues haven't had much insurance in the department.#2 Edouard Mendy makes another big mistakeMendy against West Ham United - Premier LeagueThe Senegalese shot-stopper was guilty for Chelsea conceding their first goal against West Ham United after he failed to deal with the lost ball properly.His error allowed Antonio to open the scoring for the Hammers in the 63rd minute, thus depriving the Blues of a clean sheet.CFO@CFOpinionsEdouard Mendy’s falloff has been drastic, his form has been poor of lately and some say he hasn’t been the same since AFCON. He’s making too many mistakes and his distribution was never the best but he gets in trouble with it more often now. Could be benched soon.6Edouard Mendy’s falloff has been drastic, his form has been poor of lately and some say he hasn’t been the same since AFCON. He’s making too many mistakes and his distribution was never the best but he gets in trouble with it more often now. Could be benched soon. https://t.co/0i1rzWEkvLThis isn't the first time that Edouard Mendy has made a costly mistake in goal this season. Recall that he made a blunder against Leeds at Elland Road.Mendy's recent performances in goal haven't been encouraging enough and he has been without a clean sheet in his last five league outings.