Arsenal started with Calum Chambers and Rob Holding in defence.
Costa scored only 12 goals in the last campaign with Chelsea.
Wenger had to make 2 substitutions as Iwobi pulled up with a thigh injury, while Ramsey suffered a hamstring problem.
The Gunners lost their opening league game of the season at home to Liverpool.
Rose wins golf's first gold medal since 1904.
Arsene Wenger begins his 20th season in north London with the visit of Liverpool
Chelsea kick-start the 2016/17 Premier League season against West Ham on 15 August.
Luis Enrique's side begin season in earnest with Spanish Super Cup first leg clash against Sevilla.
Jose Mourinho takes charge of his first competitive game as Manchester United manager.
Arsenal last won the league 12 years ago and Wenger fancies the team's chances this season.
Eriksen's agent denies his client wants £150,000 a week as part of a new deal.
Manchester United duo Marcus Rashford and Memphis Depay will not be sold.
Granit Xhaka is set to make his Premier League debut against Liverpool.
Gary Neville is back as a pundit after his disastrous spell with Valencia.
Jose Mourinho has sanctioned a move for the Portugal international, with an official bid expected this week.
Mustafi has been linked with a move to the Emirates this summer.
Manchester United kick start the 2016/17 PL season with a trip to Bournemouth.
Erik Lamela rescued a draw for Spurs after Ross Barkley opener.
The Foxes become first defending champions to lose opening game for 27 years.
Jurgen Klopp's men will travel to the Emirates as Liverpool face Arsenal.
Arsenal face Liverpool in their opening game of the 2016/17 Premier League campaign.
Santos confirm Thiago Maia and Gabigol Barbosa have held discussions with the Premier League pair.
Liverpool manager says Danny Ings will remain at the club after full return from injury.
Medal tally in rowing competition grows to five in Rio with two historic displays.
South Korea take on Honduras in the third quarter-final game of the Rio Olympics men's football event.
Brazil take on Colombia in the quarter finals of the Rio Olympics men's football event
The Portuguese coach praises club for signing main targets in advance of deadline day.
Germany international succeeds Mikel Arteta as Gunners' skipper.
Portugal face Germany in the Men's football quarter-final clash on Saturday.
Contractors also wrote 'dirty scousers' and 'MUFC' as they build new main stand.