Brendan Rodgers has said Liverpool must sign proven first-team talent when the transfer window reopens in January to maintain their pursuit of Champions League qualification.

Defeat at Premier League leaders Arsenal last Saturday highlighted several shortcomings in the Liverpool squad, albeit one without Glen Johnson, who had to have hospital tests because of a jaw infection, and strengthened by the return from injury of Philippe Coutinho in the second half at the Emirates Stadium.

Liverpool spent almost £50m improving the depth of Rodgers's squad in the summer but, while insisting his plans have not altered as a consequence of the performance against Arsenal, the manager admits enhancing the first team has to be a priority in January. Coutinho and Daniel Sturridge helped spark a revival in the second half of last season following their respective £8.5m and £12m moves from Internazionale and Chelsea and Rodgers is looking for a similar impact in the next transfer window.

"We need to bring in players for the team," said the Liverpool manager. "We've got a squad and we've got enough cover but in the future the focus is on bringing in players that can come straight in and improve our team. We did that last year and benefited from that. We know what we need to improve and we know the areas we need to improve but it's all about timing and all about affordability and can we do it? I always hope that in each window we can improve the team and if we can do that we can rightly be up there."

Rodgers accepts that shopping in January can be problematic but not impossible, as last season's additions proved. He added: "In January it's difficult but our recruitment guys are working very hard to try to identify that type of player that can come in. Last January we got Daniel Sturridge for the money we brought him in for, the same as Wilfried Bony went to Swansea, and he has been brilliant.

"There are players out there but you've got to dig deeper to get them in and sometimes they might not be household names but they could have the quality. When Daniel came in there were big question marks and he's answered those questions. Probably a lot of people had never heard of Coutinho but you can see he's a top young player. That's the challenge for us and the reality of where we are. There will be players that want to come but they'll maybe want Champions League football. We can't worry about it, we just need to find players that can make the difference for us."

On Saturday Coutinho is pressing for his first Liverpool start since damaging a shoulder on 16 September. His side face struggling Fulham and Rodgers insists the gifted Brazilian can slot easily into the 3-4-1-2 system he has employed successfully of late – Arsenal apart – but indicated he may revert to a more trusted formation when Martin Jol's men visit Anfield.

"For me, he is a total footballer and he can play in any system," the Liverpool manager added. "His style and his footballing arrogance dictates that he can go in and play in any system. The system has worked well for us. The reason we changed to it was because we were without a number of players. The system I will always prefer is 4-2-3-1 or 4-3-3 but obviously at times you have to look at the players you have available to maximise what you can get from them. The players have done very well in this recent system and with Glen Johnson and Coutinho back it gives us a chance to look at it again.

"You saw at Arsenal that, despite being out for so long, Coutinho came in and was at the level of [Mesut] Özil in terms of confidence and arrogance. He was as good as anyone on the field and he's just turned 21 years of age. He has a big, big future ahead of him."