Arsene Wenger is pleased to have a "committed and focused" player on board after Henrikh Mkhitaryan arrived at Arsenal in a swap for Alexis Sanchez.
Arsenal allowed Sanchez to join Manchester United on Monday to avoid losing the Chile international on a free transfer when his contract expired at the end of the season.
The Gunners received Mkhitaryan in exchange, with Wenger confirming the Armenia international has signed a contract running until June 2021.
Adding a dedicated professional to the squad provided some joy for Wenger in a transfer window he described as "more disturbing than ever".
"The thinking behind the deal is that we have player who has four months contract basically and we move [him] out for free and in exchange we have a player in Mkhitaryan who has a three-and-a-half-year contract," Wenger told Arsenal Player.
"So first it makes sense on a negotiations point of view and secondly we're replacing a very good player with a very good player, a world-class player with a world-class player. That's what it's about, to keep our strength in the team.
"I'm very excited to get a player in who will be committed and focused. That is of course as well very important, where we go into a very important period in the season where every game is basically a very important game so it's important to have players who are focused.
"I must say this transfer period has been a bit more disturbing than ever in the middle of the season, and I'm quite happy when the period is over."
Arsenal have been heavily linked with Pierre-Emerick Aubameyang, with Borussia Dortmund claiming the Gunners made a bid for over the weekend.
Wenger hopes Mkhitaryan, who scored five goals in 39 Premier League appearances for United, can find the net frequently and add creativity alongside Mesut Ozil, another player whose future at Emirates Stadium is uncertain amid protracted contract negotiations.
"Mkhitaryan can play on the wing or in midfield, so I believe he can play very well in many positions," said Wenger.
"That can help us as well because he can play together with Ozil as well as playmaker, so overall it's a good move.
"Maybe where he's a bit short is on goalscoring but he has improved that. If you look at the number of goals he's scored in his career, it's quite impressive overall.
"It is vital as well to have players who have experience, because we have a very good bunch of young players but we know that it's not sufficient in the Premier League today to put them all in together. You also need a good weight of experience in your team and he will contribute to that."