The two big-money deals followed close on the heels of Wales winger Gareth Bale's world record move from Tottenham Hotspur to Real on Sunday worth 100 million euros ($131.88 million).
After a quiet start to deadline day, things began hotting up when Arsenal smashed their club record by spending 42.5 million pounds ($66.15 million) on Ozil.
The fee eclipsed the previous highest of 15 million pounds that the North London side paid for Russia forward Andriy Arshavin in 2009.
It was also the first major signing of the window for Arsenal manager Arsene Wenger who had been heavily criticised by the fans and the media for not buying new players.
"I have said throughout the summer that we have been working hard to bring in top-quality players," he told the club website (www.arsenal.com) after landing long-term target Ozil, 24.
"This has involved many, many people across the club and I have always had the full support of the club in making decisions on the football side."
It was also all quiet on the north-western front at Arsenal's Premier League rivals Manchester United until manager David Moyes ended his long pursuit of Fellaini by returning to his former club Everton to sign the mop-haired Belgian.
Fellaini, 25, cost the Premier League champions $43 million, Everton said on their website (www.evertonfc.com).
Everton were also busy recruiting on deadline day, signing young Chelsea striker Romelu Lukaku and ex-England midfielder Gareth Barry on season-long loan deals and buying playmaker James McCarthy from Wigan Athletic for $20 million.
Everton's Merseyside rivals Liverpool had completed three deals earlier in the day.
The league leaders signed central defenders Mamadou Sakho and Tiago Ilori from Paris St Germain and Sporting Lisbon respectively for a combined fee of $39 million and took Nigeria winger Victor Moses on a season-long loan from Chelsea.
Outside the English top flight, Kaka heading back to AC Milan on a free transfer after four forgettable years at Real Madrid topped the list of notable transfers on deadline day.
The Rossoneri moved quickly after selling fellow playmaker Kevin-Prince Boateng to Schalke 04 over the weekend.
Real Madrid loaned Russia forward Denis Cheryshev to La Liga rivals Sevilla for the rest of the season but otherwise the last day of the window was low-key in continental Europe.
Earlier in the window, Neymar's move from Santos to Barcelona to partner Lionel Messi was a standout deal while Mario Goetze swapping Borussia Dortmund for rivals and European champions Bayern Munich for $48.80 million raised eyebrows.
The other big deals involving German clubs featured Henrikh Mkhitaryan moving from Shakhtar Donetsk to Dortmund for $37 million and Thiago Alcantara leaving Barca for Bayern for $35 million.
Neymar's move, the highest-profile transfer in Spain apart from Bale, was actually sealed at the end of last season when Barca announced they had secured the services of the Brazil forward for a fee of $75 million.
As well as buying Bale, Real shopped among their La Liga rivals and bought playmaker Isco from Malaga and midfielder Asier Illarramendi from Real Sociedad for $39.5 million each.
They also sold three players to Napoli, including Argentina striker Gonzalo Higuain, where they joined up with Spanish coach Rafa Benitez.
Aside from Real and Barca, the world's richest clubs by income, La Liga's cash-strapped teams generally had to sell off their top talent, continuing the trend of recent years.
Sevilla cashed in on Alvaro Negredo and Jesus Navas, selling the Spain pair to Manchester City for $33 million and $26 million respectively.
City also invested in Fernandinho from Shakhtar for $55 million while Valencia offloaded Spain striker Roberto Soldado to Tottenham for $40 million.
In France, champions Paris St Germain went into action late as they first had to find a replacement for coach Carlo Ancelotti who left for Real Madrid.
Having appointed Laurent Blanc, their first signing was Edinson Cavani from Napoli for $84 million, a fee second only to the Bale deal in this window.
PSG, who have signed two dozen players since the Qatari fund QSI bought them in 2011, then limited their moves to a couple of exciting youngsters in defenders Marquinhos and Lucas Digne for $42 million and $20 million.
They beat Monaco to Digne but the wealthy principality club had already struck deals with Colombia striker Radamel Falcao, compatriot James Rodriguez and Portuguese Joao Moutinho for a total of $171 million.
The promoted side, who are aiming to compete for the French title as early as this season, also brought in some experience with centre backs Ricardo Carvalho and Eric Abidal, on free transfers, and former France midfielder Jeremy Toulalan.
They then splashed out another $26 million on France midfielder Geoffrey Kondogbia after signing a host of great prospects like Spain Under-20 defender Borja Lopez.
No Ligue 1 club could compete with the wealthiest and last term's runners-up Olympique Marseille put their faith in youth by signing Lille's France Under-20 forward Florian Thauvin.
Media reports said they paid $20 million for the 20-year-old Thauvin, who skipped training for a week to force his way out of a club he never played for. Marseille also brought in midfielder Mario Lemina, another Under-20 world champion, from Lorient.
They signed France winger Dimitri Payet, midfielder Gianelli Imbula and forward Saber Khalifa for a total of $29 million.
($1 = 0.6425 British pounds)
($1 = 0.7582 euros)