Arsene Wenger has warned Arsenal must be "switched on" from the moment they step out in front of 40,000 fans at Elland Road tonight - or face being dumped out of the FA Cup.
The Gunners boss is again expected to rotate his starting XI for what will be their sixth fixture of a congested January after needing a last-minute penalty from captain Cesc Fabregas to deny the npower Championship side a famous win at Emirates Stadium 10 days ago.
After watching his team return to winning ways with a convincing 3-0 victory over West Ham having been well below par in the shock 1-0 Carling Cup semi-final first leg defeat away to Ipswich, Wenger knows Arsenal must continue that improvement tonight.
Nicklas Bendtner and Marouane Chamakh were both unused substitutes for the 3-0 win at Upton Park, which kept up Arsenal's Barclays Premier League title challenge.
Czech winger Tomas Rosicky is expected to be involved tomorrow having recovered from a virus, while there could also be a first start for midfielder Aaron Ramsey after his return to action from a broken leg.
Wojciech Szczesny will again be in goal as Lukasz Fabianski remains sidelined with a shoulder problem, while full-back Bacary Sagna is available after completing a three-man ban.
Wenger accepts he maybe did not get the balance of his side right against Leeds at Emirates Stadium, but is in no doubt the travelling squad will be fully focused on the test which awaits them in Yorkshire tonight.
"The speed of our display, the speed of thought, the sharpness of our game has to improve," he said.
"We want to be sharper and more positive, we started the game a little bit off our usual level. That means first, mentally, of all you want to switch on much quicker."
Arsenal have a fine away record this season, and can certainly expect a testing atmosphere at Elland Road, a venue which not so long ago hosted such showdowns on a regular basis.
Wenger, though, feels his squad will not suffer from stage fight.
"No matter what they do, the fans will be behind the team at Leeds. On the other hand, we are used to that and that would not be any excuse for us," he said.
"We have played all over the world, everywhere, in vociferous stadiums. I don't think that will be any excuse for us, it's natural and normal.
"What's important is that you show your quality no matter in what kind of environment you play."
Wenger, meanwhile, admits his search for a new centre-back is going "nowhere" - but only because it is tough to match the quality he already has in the Arsenal defence.
The Gunners are short of cover at the heart of their backline, with both Thomas Vermaelen and Sebastien Squillaci sidelined.
Spanish youngster Ignasi Miquel, 18, has been promoted from the reserves to the first-team squad, and is likely to be included again tonight.
Wenger continues to look for experience, and has been linked with moves for the likes of Bolton's Gary Cahill, Werder Bremen stopper Per Mertesacker and also veteran Aston Villa centre-half Richard Dunne, yet maintains he is no closer to delivering a top-quality target.