Italy won convincingly to finish top of Group E and eliminate the Czech Republic from the World Cup.
Materazzi scored within minutes of his introduction
Substitute Marco Materazzi scored the opening goal with a powerful header from Francesco Totti's corner.
The Czech's hopes of progress effectively ended when Jan Polak was sent off for a second bookable offence in first-half stoppage time.
And Filippo Inzaghi killed the game off near the end when he broke from almost halfway to round Petr Cech and score.
The Czech Republic had started the tournament in superb form by beating the USA 3-0, but their fortunes changed when Jan Koller went off with a hamstring injury near the end of that game.
Devoid of a focal point in attack, they were convincingly beaten in their next game by Ghana and failed to produce their best form against Italy.
The Italians were not hugely impressive, but did enough to win and set up a seemingly straightforward passage to the semi-finals.
They will face Australia in the second round and, if they win that, probably the Ukraine or Switzerland in the quarter-finals.
Skipper Pavel Nedved was inevitably prominent for the Czech Republic in the opening stages.
Milan Baros was put through by a delicious curling pass from Nedved after nine minutes, but the Aston Villa striker's touch was heavy and Gianluigi Buffon smothered.
Minutes later, Nedved tested his Juventus team-mate Buffon with two searing drives from the edge of the area.
Francesco Totti was at the heart of many of Italy's attacks, but his side lacked fluidity in the early stages.
Polak's sending off knocked the stuffing out of the Czech Republic
Their first goal came from the unlikely source of Materazzi, who had come on in place of the injured Alessandro Nesta after 26 minutes.
Totti delivered an inswinging corner from the right and the Inter Milan defender rose above Jan Polak to power in a header from nine yards out.
The goal knocked the Czech Republic's confidence. Their early exuberance petered out and Baros began to look isolated in attack.
And their predicament became even worse when Polak was shown a red card after two minutes of first-half stoppage time.
The defender, who had earlier been booked for a crude challenge on Mauro Camoranesi, brought down Totti from behind and was given a second yellow.
Totti made the most of the tackle by rolling around theatrically, but the referee had little option but to send Polak off.
Czech coach Karel Bruckner brought on skilful winger Jiri Stajner in place of veteran Karel Poborsky at the interval and his side pushed forward in search of goals.
The talismanic Nedved surged forward from midfield to find himself one-on-one with Buffon after only a few minutes.
His shot was blistering, but too close to the keeper, who parried.
The increasing adventurousness - and numerical disadvantage - of the Czech Republic inevitably left space for Italy.
Inzaghi, who came on for Alberto Gilardino after 61 minutes, wastefully put a header wide after a jinking run from Andrea Pirlo.
But he made no mistake three minutes from the end when he evaded the offside trap to advance unhindered from the halfway line and round Cech to score.
Czech Republic: Cech, Grygera, Kovac (Heinz 78), Rozehnal, Jankulovski, Plasil, Polak, Nedved, Poborsky (Stajner 46), Rosicky, Baros (Jarolim 64).
Subs Not Used: Blazek, Galasek, Jiranek, Kinsky, Koller, Mares, Sionko.
Sent Off: Polak (45).
Italy: Buffon, Zambrotta, Cannavaro, Nesta (Materazzi 17), Grosso, Camoranesi (Barone 73), Pirlo, Perrotta, Gattuso, Totti, Gilardino (Inzaghi 60).
Subs Not Used: Amelia, Barzagli, Del Piero, Iaquinta, Oddo, Peruzzi, Toni, Zaccardo.
Goals: Materazzi 26, Inzaghi 87.
Ref: Benito Archundia Tellez (Mexico).
Fifa man of the match: Marco Materazzi
Italy have extended their unbeaten run in all international matches to 21. This marks the longest streak for the Italians since 1935-39 when they remained unbeaten for 30 matches. This victory ensured Italy have progressed from the group phase for the eighth consecutive time and the 11th time in total.
Substitutes Filippo Inzaghi and Marco Materazzi became the second and third oldest scorers ever for Italy at the World Cup. Daniele Massaro is the oldest Italian to score in the finals. In 1994 he was 33 years and 36 days old when he netted against Mexico. Materazzi had never scored before in 28 previous international matches. Inzaghi notched his 22nd goal for Italy in his 50th international match. It was the 13th Italian World Cup goal scored by a substitute, more than any other nation.
Jan Polak's red card was the sixth for a player from the Czech Republic / Czechoslovakia at the World Cup and the second at this tournament following Tomas Ujfalusi's dismissal against Ghana. The Czech Republic have failed to survive the group phase of a World Cup for the fifth time in nine tries.
Trivia stats source: Infostrada Sports