Chelsea won most of their key battles on the pitch as the champions of Europe won 2-0 at the home of their London rivals Arsenal. Goals from Romelu Lukaku and Reece James early in the first half were enough to secure all three points for the visitors in a Matchday-2 Premier League game.The arrival of Romelu Lukaku from Inter Milan meant that Thomas Tuchel could start with his record-breaking signing at the Emirates. The Belgian striker was brilliant on the night, not only in attacking Bernd Leno's goal but also in involving his teammates, thanks to his trademark hold-up play.But the Man of the Match was surely right wing-back Reece James. He assisted Lukaku's first goal and then scored Chelsea's second twenty minutes later while also terrorising Kieran Tierney on the right-wing all night.Though Arsenal put up an inspired display at the start of the second half, Chelsea closed down the game after taking a two-goal lead. Arsenal's substitutes couldn't make much of an impact as Mikel Arteta's men came up second best on the night.London is Blue. 🔵 pic.twitter.com/Kkb9r4AeOb— Chelsea FC (@ChelseaFC) August 22, 2021On that note, here's a look at the top five talking points of the game as Chelsea eased past their cross-town rivals to go top of the Premier League table.#1 Romelu Lukaku's hold-up play terrorises the Arsenal defenceRomelu Lukaku of Chelsea celebrates after scoring Chelsea's first goal.When asked about his tremendous goalscoring form for Inter Milan, Romelu Lukaku was all praise for former coach Antonio Conte."For the first month, the gaffer had me training with my back facing the goal," said Lukaku.Conte had earlier tried to sign the Belgian for Chelsea, but had to settle for Alvaro Morata. But with his wish getting granted at Inter, Conte knew he had to exploit Lukaku's hold-up playing qualities.That was evident on Sunday night. The new Chelsea forward terrorised the Gunners' backline through his ability to hold the ball with his back towards goal, while his teammates covered the ground in wider positions. It was this attribute that led to him scoring his first goal within 15 minutes of his return to England.Right place, right time! 👊 🔴 0-1 🔵 pic.twitter.com/YCtriCs5wP— Chelsea FC (@ChelseaFC) August 22, 2021The big mistake Arsenal defenders made during this period was giving Lukaku a turn with the ball, something that cost the Gunners at least one goal on the night.The absence of new signing Ben White also made sure the red half of London were without their best back-four. But with Lukaku in such form, it is difficult to believe the result could have been anything else.#2 Chelsea exploit Arsenal's inefficiency on the left wingArsenal's Bukayo Saka put up a dismal show on the night.The tactic Mikel Arteta got wrong on the night was the space on the left wing between Bukayo Saka and Kieran Tierney. Chelsea right-back Reece James made Arsenal pay for it every time he received the ball on the touchline, or even in the half-spaces. The young English wing-back also scored his much-deserved goal by capitalising on the same.Saka often failed to track back during a Chelsea counter, which left Tierney one-on-one with James and Cesar Azpilicueta lurking in the overlap. That was too much of an overload for the Scottish defender, and the Blues were able to double their lead on the night.It ends in defeat at Emirates Stadium#ARSCHE— Arsenal (@Arsenal) August 22, 2021Moreover, during Arsenal's transition, Tierney also made overlapping runs on the wing, which left the defence quite open when the hosts lost the ball in the final third. Tuchel's men were quick to exploit the void left open by the two wide Arsenal players, and they did that very proficiently.