Arsenal’s failure to win a trophy since 2005 has been largely down to two things: their vulnerability in defence and their failure to dig out victories in tight games. So far this season, however, both areas look greatly improved for Arsene Wenger’s side, with an impressive win at West Ham a classic example of their new solid, winning mentality. You’d be tempted to put in a free bet or two on Arsenal finishing in the top two if City and United keep stumbling throughout the season.Their defence is looking as settled and reliable as it has done in a long time.Wojciech Szczesny’s injury was seen as a blow but Vito Mannone has filled in admirably and, barring an error against champions Manchester City, his run in the side has been impressive. Szczesny is still the better ‘keeper and will return when fit, but having two players in the same position in form is a nice headache for Wenger to have.The two young full backs, Carl Jenkinson and Kieran Gibbs, are both in fine form and are showing maturity beyond their tender years. While Gibbs has been touted as a future England left back for a number of years now, Jenkinson has not, and his performances have been a huge bonus in the absence of the hugely consistent Bacary Sagna. When Arsenal lost 8-2 at Old Trafford last season Jenkinson looked horribly out of his depth, eventually being dismissed on a miserable afternoon for the 20 year old. To have improved so much in just a year is a testament to him.Wenger has chopped and changed his central defensive pairing frequently, but it doesn’t seem to have affected the side much, if at all. A regular defensive pairing is often the cornerstone of a top side, but Arsenal have three players all vying for a starting place, and they are all equally comfortable playing alongside one another.Thomas Vermaelen and Laurent Koscielny have carried on their fine form from the end of last season and, barring disappointing displays from both in the defeat to Chelsea at The Emriates, they are a very reliable partnership. Vermaelen has excelled in his role as captain, with his marauding, gutsy style making him a crowd favourite at The Emirates. Koscielny, meanwhile, is one of Arsenal’s most improved players, and although he is sometimes guilty of switching off in crucial areas he is very consistent on the whole.Per Mertesacker has silenced his critics and adjusted to life in the Premier League superbly. At times last season he was seen as a joke figure by rival fans, with his lack of pace looking like a serious issue. Since then, his positional sense and reading of the game has seen him keep the likes of Sergio Aguero and Luis Suarez very quiet in testing away games. He has shown why he has won 82 caps for GermanSteve Bould’s appointment as assistant manager has clearly had a hugely positive effect on the whole team’s defensive work, and Wenger will be delighted with his decision to make the ex-Arsenal defender his deputy.Another key factor in Arsenal’s new found grittiness has been the excellent displays of Mikel Arteta in the heart of the midfield. When Wenger signed the Spaniard last year it was seen by many as a panic buy, having lost Cesc Fabregas to Barcelona and Samir Nasri to City. After a solid if unspectacular first season at the club he has been one of the standout players for Arsenal this time around, combining a terrific football brain with relentless hard work and the ability to break up opposition attacks.Since the days of Gilberto Silva, Arsenal have lacked someone who is top class at just sitting in the midfield and not venturing forward. Arteta does this perfectly. The likes of Fabregas, Nasri, Mathieu Flamini and Aleksandr Hleb were all great talents but they lacked Arteta’s discipline and authority. Jack Wilshere’s return from injury will only make this area of the pitch stronger for Arsenal, while Abou Diaby was exceptional before another injury setback. Even Aaron Ramsey, who at times has become something of a fall guy with the Arsenal fans, has played well whenever called upon in recent games.Experience is a huge factor in Arsenal’s resurgence, with Wenger finally remembering that a combination of older players and youngsters is vital when it comes to trying to win trophies. You only have to look at Wenger’s side of the late 1990′s and the ‘Invincibles’ team to see that.The nucleus of this current side is of a very good age, with Vermaelen, Koscielny, Mertsacker, Arteta, Cazorla, Podolski and Diaby, among others, all between 25 and 30, and with years of experience at the top level behind them.Manchester United’s ability to win countless games in the last minute over the years is not down to luck, but actually due to the likes of Ryan Giggs, Paul Scholes and Wayne Rooney gaining years of experience of tight situations. Arsenal are showing progress in that respect now.