Nova struck out a career-high 10 and the Yankees beat the Chicago White Sox 7-2 on Thursday night, completing a four-game sweep and winning their seventh in a row overall.
"That might be as good as we've seen him all year," Girardi said. "This start and Cincinnati. He was excellent tonight. His slider, again, made a huge difference for him."
The Yankees moved into a tie with Boston for the AL East lead. The teams begin a three-game series at Fenway Park on Friday night.
Nova (10-4) pitched 7 2/3 innings and won his sixth consecutive decision. He held Chicago to one run and six hits and didn't walk a batter. His approach was simple.
"Be aggressive, try to get ahead of the hitter," Nova said. "Slider today was unbelievable. Command was there. Everything was working good."
The Yankees are using a six-man starting staff on their current turn through the rotation and it's been assumed that the rookie Nova would be the odd man out, especially after Phil Hughes threw six shutout innings on Tuesday.
"I don't know," Girardi said. "We'll continue to talk about it. We've got a good problem. We've got a lot of people throwing the ball well and I'd like to keep it that way."
Girardi already announced that Hughes would start for New York on Tuesday against the Angels. In light of Nova's performance, he's not sure what's next.
"I don't have an answer for that yet," Girardi said. "We don't have to rush and make a decision what we're going to do. Eventually we'll have to."
Nova has a 2.92 ERA over his last eight starts. He's already been sent to Triple-A once this season despite his lofty totals. He insists he'll be ready no matter where his next start comes.
"Again in five days," Nova said. "Have a game in five days, no matter if it's here or anywhere else.
"I'm happy right now because I won today. I'm not frustrated. I'll keep waiting and hopefully I'll stay here."
Russell Martin hit a three-run homer in the ninth to break open the game and send Chicago to its sixth straight loss. He drove in four runs.
Robinson Cano homered, singled, walked and scored a pair of runs as the Yankees won their sixth straight over Chicago, a streak during which they've outscored the White Sox 49-14.
"That was a good pitch, that guy's out of this world, especially right now," said White Sox starter Phil Humber. "He's so locked in, so balanced, the swings he took this series, pretty impressive.
"That pitch right there was on the corner, maybe an inch or two above the knees and just to flick it out of the park like that is pretty impressive. Their whole lineup right now is hot, it's definitely a tough one to go through."
The White Sox have lost six straight games after getting to the .500 mark and drawing within three games of the lead in the AL Central last Friday.
Chicago absorbed its first four-game sweep at home since dropping four in a row to Boston from Aug 23-26, 2007. The last time the White Sox were swept at home in a four-game set against New York was June 17-20, 1976.
"We just run into a pretty hot ballclub and we not playing well against them," said White Sox manager Ozzie Guillen.
Paul Konerko had two singles for a quiet White Sox offense in his first start since Sunday. He missed the three previous games with bruised left leg.
"Hitting-wise I felt not bad," Konerko said. "I felt maybe 80 or 90 percent. Definitely, for the most part, could do what I wanted to do."
Adam Dunn homered in the ninth, a possible good sign for the struggling slugger, though it came with his club six runs down.
"Yeah, I mean they feel good, it's just meaningless," Dunn said. "Personally it felt good, but it meant nothing, had no impact on the game."
Humber (8-8) lost his fourth straight start. He went 6 1/3 innings, allowing five hits and four runs.
Entering the game, the players currently on the Yankees' were a combined 0 for 18 lifetime against Humber. He retired the first four batters on Thursday before Cano came up in the second.
With one out in the inning, Cano lined the first pitch he saw from Humber into the left-field bullpen for the first run of the game. It was Cano's 18th homer of the season and second in as many games after he'd gone 14 games without a longball.
Nova had good stuff early, retiring the first seven White Sox in order, the last three on strikeouts.
The Yankees regained the lead in the sixth thanks to the speed of Brett Gardner, who started the inning with a double to right and went to third on Jeter's sacrifice bunt.
Curtis Granderson hit a hard grounder to Dunn at first base and Gardner broke for the plate. Dunn stepped on the bag to retire Granderson and threw home, but Gardner slid home safely just ahead of the tag by catcher A.J. Pierzynski.
"I thought after Robbie's home run, we manufactured runs well," Girardi said. "Gardy starts with a double, Chief moves him over. Great baserunning by Gardy, the speed to score. I thought we manufactured well tonight."
That was it for Humber, who was replaced by Jesse Crain after throwing 94 pitches. Swisher scored on Martin's sacrifice fly to deep center.
Next up is the Yankees' biggest rival, Boston, in a park New York has struggled in this season. Girardi says it's gratifying to enter the series in a dead heat.
"I think it says that we've been playing well," Girardi said. "We've been chasing them for a while now. It just says a lot about this club and what we've been through. We've overcome some things. It is significant."
Konerko had been out since being hit in the left knee by a pitch against Boston last Sunday. Manager Ozzie Guillen said Konerko would be limited to designated hitter duty for a few days. Bartolo Colon will start for the Yankees in the series opener against Jon Lester. New York is 454-458 all-time at Fenway. However, the Yankees are 1-8 vs. Boston this season and have lost seven straight at Fenway. Colon has lost both of his starts against the Red Sox this season, once each at Boston and New York. Mark Buehrle gets the call for the White Sox in their opener at Minnesota in a key series for two teams scrambling to stay in the AL Central race. The Twins have beaten the White Sox in seven of eight meetings this season and have won 29 of their last 36 against Chicago. Buehrle has posted a 2.03 ERA over his last eight starts but is just 2-1 over that stretch. He's allowed three runs or less in 16 straight starts. ... White Sox speedster Juan Pierre was thrown out stealing in the sixth. He's just 16 for 29 on the basepaths this season.
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