Steven Gerrard's 76th-minute penalty kept Liverpool clear at the top of the table with victory over Portsmouth.
Gerrard scored after Papa Bouba Diop undid his side's resolute performance by handling a corner in Pompey boss Tony Adams's first game in charge.
Until then, Dirk Kuyt's shot against the post was the closest Liverpool had come to a goal.
Yossi Benayoun was also denied for the home side after a last-ditch Sylvain Distin tackle before Gerrard's winner.
Pompey belatedly pushed forward in search of an equaliser after the goal but Liverpool held on for a win to stay three points clear at the top of the table.
However, it was a close call for the Reds after manager Rafael Benitez had made four changes from the side that beat Chelsea on Sunday.
Portsmouth were clearly intent on stifling Liverpool as Adams employed Peter Crouch as a lone striker, dropping striker Jermain Defoe to the bench and playing with a five-man midfield.
The tactic appeared vulnerable as Liverpool's early passing and movement showed an intent which suggested the home side would earn a breakthrough.
A diagonal Kuyt shot was palmed against the post by former Reds keeper David James, while an unmarked Lucas Leiva headed over from a Fabio Aurelio corner which was just too high for him.
But Pompey survived the early scares and had a chance to stun the Anfield side against the run of play.
Bouba Diop had stolen in between Liverpool's two centre-backs and had a free header from a Sean Davis cross but struck his effort tamely and straight at keeper Jose Reina from six yards.
Liverpool heeded the warning and again began to assert their authority as they probed patiently for an opening.
Kuyt put a shot into the side-netting, a Gerrard strike was parried by James before being cleared and Alvaro Arbeloa sent a curling strike just wide - but a goal continued to elude the home side.
The longer the game progressed the more Pompey justified Adams's tactics as the visitors continued to hold the Reds at bay.
But there was also more urgency in the Reds' play and Kuyt should have done better but mistimed a header from a promising position 12 yards out.
Benayoun was later put clean through but Kaboul's sliding tackle diverted the Israeli midfielder's effort wide.
It appeared Liverpool would have to settle for a draw but they were rewarded for their perseverance.
Bouba Diop needlessly handballed a corner and allowed Gerrard to secure a hard-fought win, despite a late John Utaka header going wide.
Portsmouth manager Tony Adams:"I made sure we were tough to beat but unfortunately one moment of madness cost us.
"I'm certainly not going to have a go at Bouba Diop as he has worked his socks off."
He added: "I'm very pleased (with our play) but it we come away with nothing. I thought we deserved something."
Liverpool boss Rafael Benitez:"We knew it would be difficult.
"Always when there is a new manager players want to impress. We had our chances but you have to score."
The Reds are top of the Premier League and he added: "Confidence is high but there's long way to go."
Liverpool: Reina, Arbeloa, Hyypia, Carragher, Aurelio, Pennant (Benayoun 63), Alonso, Leiva Lucas, Babel (Riera 71), Gerrard (Keane 90), Kuyt.Subs Not Used: Cavalieri, Dossena, Agger, Mascherano.
Goals: Gerrard 76 pen.
Portsmouth: James, Pamarot, Kaboul, Distin, Belhadj, Utaka (Defoe 85), Davis, Diop, Diarra (Hughes 80), Armand Traore (Kranjcar 64), Crouch.Subs Not Used: Ashdown, Kanu, Mvuemba, Hreidarsson.
Booked: Diarra, Diop.
Ref: Steve Tanner (Somerset).