Celtic leapfrogged Rangers at the top of the Scottish Premier League with a workmanlike win over Hibernian.
Former Hibs midfielder Scott Brown broke the deadlock after five minutes with a superb volley from 18 yards.
A lacklustre encounter came to life with two goals within 10 minutes after the break, with a Glenn Loovens header sneaking in to stretch Celtic's lead.
Riordan's fantastic chip minutes later gave Hibs renewed impetus, although an Efrain Juarez header struck their bar.
Celtic's 14th straight league victory stretching back to last season ensured that champions Rangers need a win away to Aberdeen on Sunday if they are to return to the top of the table.
Riordan (right) pulled a goal back for Hibs at Celtic Park
Brown had returned to the Celtic midfield in place of Ki Sung-Yeung, while Charlie Mulgrew, Shaun Maloney and Cha Du-Ri came in for Mark Wilson, Georgios Samaras and the injured Emilio Izaguirre.
And the captain made an immediate impact against his former club as Celtic edged into the lead after five minutes.
Brown broke from midfield and worked a one-two with Juarez before volleying past former Celtic goalkeeper Mark Brown from long range for his first goal since March.
Hibs were without Sol Bamba and Colin Nish through injury, with youngsters David Wotherspoon and Paul Hanlon both coming into the starting line-up.
In the absence of the Ivory Coast defender and the big striker, Celtic defender Daniel Majstorovic rose above the visiting defence to meet a couple of corners without finding the target with his headers.
However, while Celtic had the better of the possession, neither side seriously threatened to turn some pretty but ineffectual passing into chances.
Hibs were playing like a side with only one win in eight games and the supply to lone striker Riordan was limited.
However, immediately after the break, Celtic handed Riordan the chance of an equaliser when Anthony Stokes, so recently a Hibs player himself, was short with a pass back, but the former Hoops forward was unable to capitalise.
Seconds later, a mistake at the other end presented Celtic with their second goal, when Loovens' flicked header from a 51st-minute corner somehow evaded goalkeeper Brown and attempts to clear off the line.
Whether it was an enforced change because of injury or a tactical one, Celtic manager Neil Lennon had started the second half with a more attacking formation, with midfielder Ki Sung-Yeong coming on for Mulgrew and Joe Ledley moving back to left-back.
The change certainly appeared to add to the excitement, although the next goal was quickly conceded by the home side's rearranged defence.
It took a moment of magic from Riordan to bring new life to Hibs' challenge, the forward sending a superb lob from the edge of the penalty box over towering Celtic goalkeeper Fraser Forster and into the net after 54 minutes.
John Rankin went close to giving Hibs a controversial equaliser when he sent a drive a few yards wide with Celtic claiming not only that they should have had the free-kick but that the visitors had stolen several yards for the set-piece.
The game came to life in the final 10 minutes, with Samaras just failing to reach a Stokes cross across the face of goal and a Juarez header striking the face of the Edinburgh side's crossbar.
Hibs immediately swept to the other end and a Riordan volley flew just over from 12 yards, but it was Celtic who ended the game on top for a deserved victory.
Live text and stats
Saturday, 25 September 2010
11 Cha Du-Ri
21 Mulgrew (Ki Sung-Yeung 46)
10 Stokes yellow card
88 Hooper (Samaras 70)
18 Ki Sung-Yeung,
33 Baram Kayal,
02 Hart (Stephens 80)
14 Dickoh yellow card
08 De Graaf (Galbraith 80)
11 Rankin (Trakys 86)
Ref: MurrayAtt: 48,625
Attempts on target
Attempts off target
90:00+2:26 The referee blows for the end of the match.
90:00+1:46 Efrain Juarez takes a outswinging corner.
90:00+0:55 Du-Ri Cha produces a cross, clearance by Paul Hanlon.
90:00+0:07 Free kick awarded for a foul by Francis Dickoh on Georgios Samaras. Scott Brown restarts play with the free kick.
89:16 Du-Ri Cha takes the chance to get an effort at goal. Save by Mark Brown.
88:32 Daniel Galbraith sends in a cross.
87:42 Georgios Samaras crosses the ball.
87:11 Unfair challenge on Daniel Galbraith by Shaun Maloney results in a free kick. Liam Miller takes the free kick.
86:30 Corner taken right-footed by Shaun Maloney from the left by-line, save by Mark Brown.
86:21 The ball is crossed by Anthony Stokes, clearance made by David Stephens.
85:46 Substitution Valdas Trakys on for John Rankin.
84:16 Corner taken right-footed by Shaun Maloney.
83:53 Georgios Samaras takes a shot. Blocked by Francis Dickoh.
83:16 Handball decision goes against Daniel Majstorovic. Free kick taken by Kevin McBride.
82:50 Sung-Yong Ki has a shot on goal from outside the box which misses right.
81:32 Effort on goal by Derek Riordan from inside the area goes harmlessly over the bar.
81:04 Du-Ri Cha crosses the ball, Efrain Juarez takes a shot.
80:32 The ball is sent over by Anthony Stokes.
Correction - 79:09 Substitution Edwin De Graaf leaves the field to be replaced by Daniel Galbraith.
Correction - 79:09 Substitution Michael Hart goes off and David Stephens comes on.
Correction - 79:09 Scott Brown gives away a free kick for an unfair challenge on Derek Riordan.
79:09 Kevin McBride restarts play with the free kick.
79:09 Substitution Edwin De Graaf leaves the field to be replaced by Daniel Galbraith.
79:09 Substitution Michael Hart leaves the field to be replaced by David Stephens.
79:09 Foul by Scott Brown on Derek Riordan, awarded.
78:32 Corner taken by Sung-Yong Ki, save by Mark Brown.
78:11 Outswinging corner taken right-footed by Shaun Maloney from the right by-line, clearance by Francis Dickoh.
77:43 Outswinging corner taken by Shaun Maloney from the right by-line, Edwin De Graaf manages to make a clearance.
77:33 The ball is sent over by Du-Ri Cha.
76:26 Kevin McBride challenges Sung-Yong Ki unfairly and gives away a free kick. Daniel Majstorovic takes the direct free kick.
76:20 Liam Miller produces a cross, clearance made by Daniel Majstorovic.
75:32 The ball is swung over by Du-Ri Cha, clearance made by Michael Hart.
74:03 Foul by Efrain Juarez on Liam Miller, free kick awarded. Strike comes in from Derek Riordan from the free kick.
72:37 John Rankin has an effort at goal from outside the penalty box which goes wide right of the target.
72:18 Georgios Samaras concedes a free kick for a foul on Paul Hanlon. Free kick taken by Kevin McBride.
70:30 Scott Brown challenges Kevin McBride unfairly and gives away a free kick. Free kick taken by Paul Hanlon.
70:18 Du-Ri Cha produces a cross, save by Mark Brown.
69:39 Scott Brown crosses the ball.
69:02 Substitution Gary Hooper goes off and Georgios Samaras comes on.
68:07 Unfair challenge on Sung-Yong Ki by Edwin De Graaf results in a free kick. Daniel Majstorovic restarts play with the free
67:15 Shaun Maloney takes a shot. Save made by Mark Brown.
65:38 The ball is crossed by Edwin De Graaf.
64:28 The ball is delivered by Glenn Loovens, clearance by Ed
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.