Cueto (4-1) gave up four hits and two runs over six innings as the Reds moved into first place in the NL Central by a half-game over St. Louis. The right-hander improved to 4-0 with a 2.18 ERA in his last five starts — including a one-hit shutout of Pittsburgh on May 11.
The Indians stranded two runners in the eighth and ninth innings. Nick Masset came on in the eighth and got Jhonny Peralta on a called third strike.
Indians starter Fausto Carmona (4-2) took the loss.
Trevor Crowe's two-run single with the bases loaded in the ninth off Francisco Cordero made it 6-4. Cordero, pitching for the third straight day and in a non-save situation, then got Shin-Soo Choo on a called third strike in a 10-pitch at-bat. Austin Kearns lined the next pitch to right fielder Jay Bruce to end it. It was Cordero's 36th pitch of the inning.
Bruce was 4 for 4 with two RBIs and Brandon Phillips had two doubles and three runs for Cincinnati, which is 18-7 since opening the season 7-11.
The Reds have won 11 of 14 from their state in-rival since 2008 and lead the all-time series 33-32.
Cleveland made three errors in its season-high sixth straight loss to drop deeper into last place in the AL Central.
Travis Hafner's two-out, two-run homer got Cleveland within 5-2 in the sixth. Cueto then walked Peralta and went to a 2-1 count on Matt LaPorta when manager Dusty Baker and trainer Paul Lessard went to the mound to check on the right-hander. Whatever was troubling Cueto didn't keep him from getting LaPorta to pop out on the next pitch.
Bruce's third straight single gave the Reds a 6-2 lead in the seventh. He added a double in the ninth.
Joey Votto and Bruce had RBI singles in the first off Carmona. Votto moved into scoring position on a throwing error by centerfielder Trevor Crowe on his hit and scored an unearned run on Bruce's line single.
Votto singled to open the fourth, stole second and took third on a throwing error by Mike Redmond. That snapped the veteran's major league record for catchers at 253 consecutive errorless games since July 22, 2004.
One out later, Nix homered into the right-field seats to make it 4-0.
Phillips reached on an error by third baseman Peralta in the fifth and eventually scored on a sacrifice fly by Scott Rolen.
Carmona allowed three earned runs and seven hits over six innings. The right-hander has worked six or more innings in eight of his nine starts.
NOTES: Indians manager Manny Acta said OF Grady Sizemore, on the disabled list with a bruised left knee, is "visiting doctors" to determine what method of treatment is best. Acta said he hopes for an update early next week. ... Cleveland signed veteran INF Josh Phelps to a minor-league contract and assigned him to Triple-A Columbus. The 32-year-old played in 24 games for the Indians in 2004 and has 64 career homers for six MLB teams since 2000. ... Former Ohio State and Cincinnati Bengals star Archie Griffin, the two-time Heisman Trophy winner, threw out a ceremonial first pitch. ... Cleveland has totaled 18 runs in its six straight losses. ... Baker said 40-year-old LHP Arthur Rhodes, who pitched three straight days, was unavailable Saturday. ... Nix is 8 for 13 (.615) with three homers, six runs and seven RBIs in his last three games.
