Following the French check at Branau, Napoleon ordered his forces to work toward consolidation and resting. As the Austrians chose this time to begin a withdrawal toward the Enns river, there were some small engagements of opportunity by the French. Archduke Charles concentrated his army at Lambach and ordered his provisional Korps to begin to build breastworks.

On April 26th, the French began a new offensive aimed at driving Charles back across the Enns. They were surprised to find that the Austrians had already abandoned Ried and so pressed on, with Gerard striking at Lambach from the southwest and Messena to hit it simultaneously from the northwest. Charles had forseen this threat though and Hiller's II Korps, operating out of Schaerding, had probed toward Ried, disrupting Massena's march. Ney would be sent in pursuit of Hiller but the Austrian attack was to delay the march on Lambach by nearly half a day. Gerard's I Corps though would arrive at Charles' army on schedule and so would face them alone.

Lefebvre's III Corps would begin to arrive in the early morning of the 28th, having marched through the night, but it was I Corps under Gerard that would be facing the bulk of Charles' army. The battle would be of two halves: In the south, before Vorchdorf, Charles would mass his Liebegarde and I Korps with the intention of destroying the French I Corps and then moving north to aid the Provisional Korps.

In the north, around Lambach, the Austrian militia would be dug in behind breastworks with the hope of slowing any French reinforcements from Ried enough to give time for the main Austrian army to destroy Gerard.

The French plan was to have Gerard hold Charles long enough that the main French army could burst through the landwehr and then cross the river to finish off the Austrians. Ultimately, Napoleon's directive for the battle was that he was willing to risk everything in an attempt to break this army of Charles'. Allowing it to retreat in good order to form a new position at Steyr or Linz was not acceptable.

Along with French III Corps' arrival, the lead elements of French I Cavalry Corps begin to show. The French orders are to break through the breastwork line, exploit the breech, and then occupy the landwehr with one corps and send everything else south. The heavy cavalry therefore will not be wasted trying to frontally assault the breastworks but will instead wait for the infantry to clear a path for them. The woods to their right would take hours to pass through so it is ruled out as an option.

In the south, the Austrians begin aggressively with five brigades of grenadiers from the Liebegarde driving forward. Two of those brigades would find themselves rudely repulsed by French light infantry in the woods while another is disordered by the fire of the voltigeurs and stalled.

The Austrian grenadiers are terribly unfortunate in their attacks and take massive casualties before they are entirely driven off. Lindenau launches a series of attacks on the far left of the Austrian line but the attacks there would also bog down.

It is Austrian artillery that does what the grenadiers could not and the French light infantry are hurled from their place in the forest.In the center of the line, three brigades of Grenzer light infantry are inflicting terrible casualties upon the French. Lobau's XII Corps arrives from Wacklabruck and the French line is bolstered when it sorely needed it. An Austrian cavalry charge would break through to hit one of the arriving march columns but the effect would be a only minor setback for the French.

In the north, the task before the Provisional Korps becomes more daunting. Elements of Ney's IV Corps have arrived following an unsuccessful skirmish at Linz but more alarming, the Imperial Guard is advancing aggressively on the hanging Austrian right wing.

It is early afternoon when the French launch assaults against the breastworks all along the line. Five thousand Frenchmen charge forward with bayonets lavelled. Behind the Landwher, General Rohan arrives from Linz with a small corps.

The line holds! Massena is repulsed along the length of the breastworks. The Guard make some progress but it is at great cost. Austrian militia are seen with Imperial bearskins held up tauntingly from behind the apparent safety of their earthworks. 

In the south, the fight becomes an even affair of thrust and parry. The two opposing forces can never seem to get a consolidated attack going so they throw brigades against one another piecemeal. In one French counter-attack, General Lindenau would be captured by French Chasseurs.

The French are not finished though and more attacks against the breastwork line begin to allow for breakthroughs. Guns are assembled to try to level the Austrian held part of Lambach village but the IV corps cavalry decide that they cannot wait for a gap to appear. They begin to fight their way through the thick, rough ground of the wood.

The bulk of the French cavalry, including several thousand cuirassier, waits though for the fall of Lambach when they can then freely wheel through it to head south.

The Austrians have been obliged to cease attacking in the south and now fall back to try to organize a defense. The French advance where they can but they are nearly a spent force themselves. Their cavalry, superior in numbers now, is loathe to bring the weight of the remaining Austrian cuirassier brigade down upon them so is cautious. One brigade of French cavalry throws caution to the wind and rides for glory. They would fall short.

Austrian X Korps would battle the Imperial Guard without fear and would achieve legendary successes. An Old Guard brigade and a Young Guard brigade would be routed by fire. While X Corps is mixing it up with the Guard, the Provisional Korps is finally overwhelmed by French III Corps. The French are pouring through the breeches at will now and flanking what defences the Austrians still retain.

The French Cavalry Corps decides that it can no longer wait for Lambach to fall and hurls itself into the dark wood in the late afternoon.

Napoleon moves to personally rally his Old Guard regiments even while the rest of the Corps continues attacking X Corps. The Austrians are paying dearly for their successes against the guard and their cavalry is routed back.

With X Corps rallying in the rear, it is only Landwehr infantry that the Austrians have to stop the Imperial Guard. Courageously, they go forward to do just that. The Provisional Korps is elsewhere shattered though and nothing can be done to prevent the French from driving deep into Austrian rally areas.

After six hours of fighting, Massena has cleared the last of the forward line of Austrian breastworks. Lambach village still defies his artillery though.

The battle in the south is decidedly in the French favour now. Gerard and Lobau press forward, knowing that the Austrian I Korps and Liebegarde are on the verge of breaking. What remains of the Liebegarde grenadiers have formed themselves into squares to face down the approaching French IV corps cavalry. Generally, the Austrians are able to fall back to form a new line of defense better than the French can advance upon it.

The sky is darkening as Lambach finally falls to the French. The Austrian Provisional Corps is broken. X Corps tries to hold out and the Imperial Guard is once more on the attack and that is when a bullet finds the heroic General Rohan and slays him.

The remnants of Austrian I Korps, the insurrection infantry from Hungary heroicly holding a line for the regulars to rally behind, stands before the bridge to Steyr. The French are not done attacking though, despite their fatigue.

The northern battle would end with X Korps and the Provisional Korps shattered. The Liebegarde is broken. I Korps too cannot help but follow the rest of the army routing across the river toward Steyr. It would be a weary I Corps that would pursue them the next day but that pursuit would be checked by a fresh VIII Corps waiting at Steyr. It has been summoned to the battle at Lambach but failed to arrive in time.

Napoleon got the decisive victory that he demanded but the cost may prove too great. The Old Guard is worn and the Young Guard weakened. I Corps and III Corps took losses that they could ill afford and the frailty of the German allies was revealed.

The 1me Cavalry Corps remains fresh.

Austrian losses are estimated at 45,500. French losses at 25,500.